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Implicit Implicit DifferentiationDifferentiation
Number of heart Number of heart beats per minute, t beats per minute, t seconds seconds
after the beginning of a race is after the beginning of a race is given bygiven by
What is your heart rate at the What is your heart rate at the beginning of the race?beginning of the race?
21400 3 204( )20
t tR t
t
Number of heart Number of heart beats per minute, t beats per minute, t seconds seconds
after the beginning of a race is after the beginning of a race is given bygiven by
Find R(0).Find R(0).
R(0) = R(0) = beats/min. beats/min.
21400 3 204( )20
t tR t
t
20 20 89.44
Number of heart Number of heart beats per minute, t beats per minute, t seconds seconds
How fast is your heart beating How fast is your heart beating after 100 seconds?after 100 seconds?
How fast is your heart rate How fast is your heart rate increasing after 100 sec? increasing after 100 sec? [Acceleration][Acceleration]
21400 3 204( )20
t tR t
t
Number of heart Number of heart beats per minute, t beats per minute, t seconds seconds
How fast is your heart beating How fast is your heart beating after 100 seconds? R(100) after 100 seconds? R(100)
How fast is your heart rate How fast is your heart rate increasing after 100 sec? increasing after 100 sec? [Acceleration][Acceleration]
21400 3 204( )20
t tR t
t
Number of heart Number of heart beats per minute, t beats per minute, t seconds seconds
How fast is your heart beating How fast is your heart beating after 100 seconds? R(100) after 100 seconds? R(100)
How fast is your heart rate How fast is your heart rate increasing after 100 sec? increasing after 100 sec? [Acceleration] R’(100)[Acceleration] R’(100)
21400 3 204( )20
t tR t
t
Number of heart Number of heart beats per minute, t beats per minute, t seconds seconds
What is your heart rate at the What is your heart rate at the end of the race?end of the race?
21400 3 204( )20
t tR t
t
Number of heart Number of heart beats per minute, t beats per minute, t seconds seconds
What is your heart rate at the What is your heart rate at the end of the race?end of the race? 2 21
400 3 20 /4lim ( )( 20) /t
t t tR t
t t
21400 3 204( )20
t tR t
t
Number of heart Number of heart beats per minute, t beats per minute, t seconds seconds
What is your heart rate at the What is your heart rate at the end of the race?end of the race?
21400 3 204( )20
t tR t
t
2 21 1400 3 20 / 4004 2lim ( ) 200( 20) / 1t
t t tR t
t t
If h(x) = [g(x)]If h(x) = [g(x)]n n thenthen
h’(x) = n [g(x)] h’(x) = n [g(x)]n-1n-1g’(x)g’(x)
We review the power rule.We review the power rule.
If y = 4(2x + 2)If y = 4(2x + 2)55 then y’ then y’ = =
A.A. 20 (2x + 2)20 (2x + 2)44 2 = 40 (2x + 2) 2 = 40 (2x + 2)4 4
B.B. 20 (2x + 2)20 (2x + 2)55 2 = 40 (2x + 2) 2 = 40 (2x + 2)55
C.C. 20(2)20(2)44 = 20 (16) = 320 = 20 (16) = 320
D.D. 20 (2x + 2)20 (2x + 2)44 = 20 (2x + 2) = 20 (2x + 2)44
If y = 4(2x + 2)If y = 4(2x + 2)55 then y’ then y’ = =
A.A. 20 (2x + 2)20 (2x + 2)44 2 = 40 (2x + 2) 2 = 40 (2x + 2)4 4
B.B. 20 (2x + 2)20 (2x + 2)55 2 = 40 (2x + 2) 2 = 40 (2x + 2)55
C.C. 20(2)20(2)44 = 20 (16) = 320 = 20 (16) = 320
D.D. 20 (2x + 2)20 (2x + 2)44 = 20 (2x + 2) = 20 (2x + 2)44
If h(x) = [3x + 1/x]If h(x) = [3x + 1/x]77
h’(x) = h’(x) =
A.A. 21 x - 7/x21 x - 7/x22
B.B. 7 [3x + 1/x]7 [3x + 1/x]6 6 [3 + 1/x[3 + 1/x22]]
C.C. 7 [3x + 1/x]7 [3x + 1/x]6 6 [3 – 1/x[3 – 1/x22]]
D.D. 7 [3 – 1/x]7 [3 – 1/x]66
If h(x) = [3x + 1/x]If h(x) = [3x + 1/x]77
h’(x) = h’(x) =
A.A. 21 x - 7/x21 x - 7/x22
B.B. 7 [3x + 1/x]7 [3x + 1/x]6 6 [3 + 1/x[3 + 1/x22]]
C.C. 7 [3x + 1/x]7 [3x + 1/x]6 6 [3 – 1/x[3 – 1/x22]]
D.D. 7 [3 – 1/x]7 [3 – 1/x]66
Replace g(x) with y.Replace g(x) with y.
Instead of ([g(x)]Instead of ([g(x)]n n )’ = n [g(x)])’ = n [g(x)]n-1n-1g’(x)g’(x)
We get (y We get (y n n )’ = n [ y ])’ = n [ y ]n-1 n-1 y’y’
Replace g(x) with y.Replace g(x) with y.
We get (y We get (y n n )’ = n [ y ])’ = n [ y ]n-1 n-1 y’y’
Recall [(x+1)(xRecall [(x+1)(x22-3)]’ -3)]’ = (x+1)(2x)+ (x= (x+1)(2x)+ (x22-3)-3)
So [(x+1)y]’ = (x+1)y’ + y So [(x+1)y]’ = (x+1)y’ + y
[3 y[3 y3 3 ]’ = 9 y]’ = 9 y2 2 y’y’
' 3 2 22
23 3
2 3 4 ' 2 (6 3)2
2 3 2 3
x x yy y xy
x x x x
So [(2x+1)y]’ = ?So [(2x+1)y]’ = ?
A.A. 2y’2y’
B.B. (2x+1) y’ + 2y(2x+1) y’ + 2y
C.C. (2x+1) y’ + 2y’(2x+1) y’ + 2y’
D.D. (2x+1) y’(2x+1) y’
So [(2x+1)y]’ = ?So [(2x+1)y]’ = ?
A.A. 2y’2y’
B.B. (2x+1) y’ + 2y(2x+1) y’ + 2y
C.C. (2x+1) y’ + 2y’(2x+1) y’ + 2y’
D.D. (2x+1) y’(2x+1) y’
Find [2yFind [2y66 + 2y]’ + 2y]’
A.A. 12y12y55 y’ – 2 y’ – 2
B.B. 12y12y55 y’ + 2y’ y’ + 2y’
C.C. 12y12y55 y’ + 2yy’ y’ + 2yy’
D.D. 12y12y55 + 2y’ + 2y’
Find [2yFind [2y66 + 2y]’ + 2y]’
A.A. 12y12y55 y’ – 2 y’ – 2
B.B. 12y12y55 y’ + 2y’ y’ + 2y’
C.C. 12y12y55 y’ + 2yy’ y’ + 2yy’
D.D. 12y12y55 + 2y’ + 2y’
Guidelines for Guidelines for Finding the Finding the Derivative ImplicitlyDerivative ImplicitlyLet y stand for one of any number of Let y stand for one of any number of
functions.functions.
Differentiate both sides of the equation, Differentiate both sides of the equation, using chain rule, power rule, product using chain rule, power rule, product rule, quotient rule.rule, quotient rule.
If xIf x22 + y + y22 = 36 find y’. = 36 find y’.
What is the derivative of xWhat is the derivative of x22 ? ?
2x2x
What is the derivative of yWhat is the derivative of y22 ? ?
2yy’2yy’
What is the derivative of 36 ?What is the derivative of 36 ?
What is the derivative of What is the derivative of 36?36?
0.00.0
0.10.1
Differentiate both Differentiate both sidessides x x22 + y + y22 = 36 = 36A.A. 2x + 2yy’ = 02x + 2yy’ = 0
B.B. 2x + 2yy’ = 362x + 2yy’ = 36
C.C. 2x + 2y = 02x + 2y = 0
Differentiate both Differentiate both sidessides x x22 + y + y22 = 36 = 36A.A. 2x + 2yy’ = 02x + 2yy’ = 0
B.B. 2x + 2yy’ = 362x + 2yy’ = 36
C.C. 2x + 2y = 02x + 2y = 0
Guidelines for Guidelines for Finding the Finding the Derivative ImplicitlyDerivative ImplicitlyLet Y stand for one of any number of Let Y stand for one of any number of
functions.functions.
Differentiate both sides of the equation, Differentiate both sides of the equation, using chain rule, power rule, product using chain rule, power rule, product rule, quotient rule.rule, quotient rule.
Place all of the terms containing Y' on Place all of the terms containing Y' on one side and the other terms on the one side and the other terms on the other.other.
If xIf x22 + y + y22 = 36 find y’. = 36 find y’.
2x + 2yy’ = 02x + 2yy’ = 0
2yy’ = -2x2yy’ = -2x
Guidelines for Guidelines for Finding the Finding the Derivative ImplicitlyDerivative Implicitly
Differentiate both sides of the equation, Differentiate both sides of the equation, using chain rule, power rule, product using chain rule, power rule, product rule, quotient rule.rule, quotient rule.
Place all of the terms containing y' on Place all of the terms containing y' on one side and the other terms on the one side and the other terms on the other.other.
Factor the y' out if necessary and solve Factor the y' out if necessary and solve for y’. for y’.
If xIf x22 + y + y22 = 36 find y’. = 36 find y’.
2yy’ = -2x2yy’ = -2x
yy’ = -xyy’ = -x
y’ = y’ = x
y
Guidelines for Guidelines for Finding the Finding the Derivative ImplicitlyDerivative Implicitly
Place all of the terms containing Y' on Place all of the terms containing Y' on one side and the other terms on the one side and the other terms on the other.other.
Factor the Y ' out if necessary and solve Factor the Y ' out if necessary and solve for Y '.for Y '.
Replace x and y by the values given. Replace x and y by the values given.
y’ =y’ = x x22 + y + y22 = 36 = 36
Top point only!Top point only!
Find the slope when x = 2.Find the slope when x = 2.
When x = 2, y = When x = 2, y = oror
Y = Y =
Thus y’ = Thus y’ =
x
y
32
236 x2
32
y’ = y’ =
Y’ = for top pointY’ = for top point
Y’ = bottom Y’ = bottom pointpoint
2 2
32 32
x
y
2
32
If y’ =If y’ =
find the slope at (-3 , find the slope at (-3 , 3)3)
1.7321.732
0.10.1
x
y
3
Thus if the dolphins Thus if the dolphins forehead could be forehead could be approximated by a circle,approximated by a circle,
we could calculate we could calculate
the slope there ifthe slope there if
we knew the x andwe knew the x and
y coordinates. y coordinates.
y’ = y’ = x
y
And if the dolphins throat And if the dolphins throat could be approximated by a could be approximated by a circle,circle,
we could calculate we could calculate
the slope there ifthe slope there if
we knew the x andwe knew the x and
y coordinates. y coordinates.
y’ = y’ = x
y
Guidelines for Finding the Derivative Guidelines for Finding the Derivative ImplicitlyImplicitly
Let Y stand for one of any number of Let Y stand for one of any number of functions.functions.
Differentiate both sides of the equation, Differentiate both sides of the equation, usingusing
chain rule, power rule, product rule, quotient chain rule, power rule, product rule, quotient rule.rule.
Place all of the terms containing y' on one Place all of the terms containing y' on one side side and the other terms on and the other terms on the other. the other.
Factor the y’ out if necessary and solve for Factor the y’ out if necessary and solve for y’. y’.
Replace x and y by the values given. Replace x and y by the values given.
Let y stand for one of 5 Let y stand for one of 5 functions. functions.
If 3xIf 3x22 + xy + xy55 = 16x find y’. = 16x find y’.
What is the derivative of 3xWhat is the derivative of 3x22 ? ?
6x6x
What is the derivative of xyWhat is the derivative of xy55 ? ?
x5yx5y44y’+yy’+y55
What is the derivative of 16x ?What is the derivative of 16x ?
Differentiate xyDifferentiate xy55 using the using the product rule and power product rule and power rulerule
x5yx5y44y’ + yy’ + y55
3x3x22 + xy + xy55 = 16x = 16xDifferentiate both Differentiate both sidessidesA.A. 6x + 5y6x + 5y44 y’= 16 y’= 16
B.B. 6x +5xy6x +5xy4 4 y’= 16y’= 16
C.C. 6x +5xy6x +5xy4 4 y’+yy’+y5 5 = 16= 16
D.D. 6 + 6x +5xy6 + 6x +5xy4 4 y’+yy’+y5 5 = 0= 0
3x3x22 + xy + xy55 = 16x = 16xDifferentiate both Differentiate both sidessidesA.A. 6x + 5y6x + 5y44 y’= 16 y’= 16
B.B. 6x +5xy6x +5xy4 4 y’= 16y’= 16
C.C. 6x +5xy6x +5xy4 4 y’+yy’+y5 5 = 16= 16
D.D. 6 + 6x +5xy6 + 6x +5xy4 4 y’+yy’+y5 5 = 0= 0
Guidelines for finding Guidelines for finding the derivative the derivative implicitlyimplicitlyLet y stand for one of 5 functions.Let y stand for one of 5 functions.
Differentiate both sides of the equation, Differentiate both sides of the equation, using chain rule, power rule, product using chain rule, power rule, product rule, quotient rule.rule, quotient rule.
If 3xy + x + 5yIf 3xy + x + 5y22 = 16 find = 16 find y’.y’.
3xy’ + 3y + 1 + 10yy’ = 03xy’ + 3y + 1 + 10yy’ = 0
Place all (y’)’s on the left and Place all (y’)’s on the left and factorfactor
3xy’ + 10yy’ = -1 - 3y3xy’ + 10yy’ = -1 - 3y
(3x+10y)y’= -1 - 3y(3x+10y)y’= -1 - 3y
y’ = y’ = 1 3
3 10
y
x y
If xIf x22 + 5y + 5y22 = 6 find y’. = 6 find y’.
2x + 10yy’ = 02x + 10yy’ = 0
y’ = -2x/10y = -x/5yy’ = -2x/10y = -x/5y
y’ = -x/5yy’ = -x/5yFind y’ when x = y = 1Find y’ when x = y = 1
-0.2-0.2
0.10.1
If xIf x22 + 5y + 5y22 = 6 find y’’. = 6 find y’’.
y’ = -x/5yy’ = -x/5y
5y(-1)-(-x)5y’ 5xy’-5y5y(-1)-(-x)5y’ 5xy’-5y
y’’ = ----------------- = -------------y’’ = ----------------- = -------------
25 y25 y2 2 25 y25 y22
Find y’’ when x = y = 1Find y’’ when x = y = 1and y’ = -0.2 and y’ = -0.2
-0.24-0.24
0.10.1
2
5 ' 5''
25
xy yy
y
Find y’’ when x = y = 1Find y’’ when x = y = 1and y’ = -0.2 and y’ = -0.2
-0.24-0.24
0.10.1
2
5 ' 5 1 5''
25 25
xy yy
y
Find dy/dxFind dy/dx
1. x1. x2 2 y + yy + y2 2 x = 6x = 6 6. (3xy + y)6. (3xy + y)3 3 = 6y = 6y
Find the equation of Find the equation of the tangent and the the tangent and the normal normal 29. x29. x2 2 + xy - y+ xy - y2 2 = 1 at (2, 3)= 1 at (2, 3) 31. x31. x2 2 yy2 2 = 9 at (1, 3)= 9 at (1, 3) 35. 2xy + 35. 2xy + x = 2 x = 2 at (1, at (1, /2)/2)
xx22 – 2xy + y – 2xy + y22sin(xy) > 4sin(xy) > 4
Find y’ at the point (-2, 0)Find y’ at the point (-2, 0)
2x -2xy’-2y+y2cos(xy)[xy’+y]2x -2xy’-2y+y2cos(xy)[xy’+y]+2sin(xy)yy’=0+2sin(xy)yy’=0
Example OnlyExample Only
Implicit Implicit DifferentiationDifferentiation
Related RatesRelated Rates
x’ = dx/dx = 1x’ = dx/dx = 1
x’ = dx/dt x’ = dx/dt
The edge of an ice The edge of an ice cube is decreasing at cube is decreasing at 2mm/sec when x = 2mm/sec when x = 400mm, 400mm, find the rate the volume is find the rate the volume is
changing at that instant.changing at that instant.
The edge of a cube is The edge of a cube is decreasing at 2mm/sec decreasing at 2mm/sec when x = 400mm, find when x = 400mm, find v’.v’. v = xv = x3 3
v’ = 3xv’ = 3x22
The edge of a cube is The edge of a cube is decreasing at 2mm/sec decreasing at 2mm/sec when x = 400mm, find when x = 400mm, find v’.v’. v = xv = x3 3
v’ = 3xv’ = 3x2 2 x’x’
The edge of a cube is The edge of a cube is decreasing at 2mm/sec decreasing at 2mm/sec when x =400mm, find when x =400mm, find v’.v’. v = xv = x3 3
v’ = 3xv’ = 3x2 2 x’x’ v’ = 3(160000)(-2) = v’ = 3(160000)(-2) = -480000 mm-480000 mm33/ sec/ sec
Related RatesRelated RatesRead the problem, drawing a pictureRead the problem, drawing a picture
No non-constants on the pictureNo non-constants on the picture
Write an equationWrite an equation
Differentiate implicitlyDifferentiate implicitly
Enter non-constants and solveEnter non-constants and solve
The edge of a cube is The edge of a cube is decreasing at 2mm/sec decreasing at 2mm/sec when x = 400mm, find when x = 400mm, find v’.v’. find the rate the volume is find the rate the volume is
changing at that instant.changing at that instant.
400 does not appear on the 400 does not appear on the drawing drawing
Set x=400 after v’ = 3xSet x=400 after v’ = 3x2 2 x’x’
Related RatesRelated RatesSuppose a painter is standing on a Suppose a painter is standing on a 13 foot ladder and Joe ties a rope 13 foot ladder and Joe ties a rope to the bottom of the ladder and to the bottom of the ladder and walks away at the rate of 2 feet walks away at the rate of 2 feet per second.per second.
Related RatesRelated RatesSuppose a painter is standing on a Suppose a painter is standing on a 13 foot ladder and Joe ties a rope 13 foot ladder and Joe ties a rope to the bottom of the ladder and to the bottom of the ladder and walks away at the rate of 2 feet walks away at the rate of 2 feet per second.per second.
How fast is the painter How fast is the painter
falling when x = 5 feet?falling when x = 5 feet?
Related RatesRelated Rates13 is a constant and appears 13 is a constant and appears
the rate of 2 feet per second [x’ = the rate of 2 feet per second [x’ = 2]2]
How fast is the painter How fast is the painter
falling when x = 5 feet?falling when x = 5 feet?
Related RatesRelated Rates13 is a constant and appears 13 is a constant and appears
the rate of 2 feet per second [x’ = the rate of 2 feet per second [x’ = 2]2]
How fast is the painter How fast is the painter
falling when x = 5 feet?falling when x = 5 feet?
NOT ON THE DRAWINGNOT ON THE DRAWING
What does the What does the Pythagorean Theorem Pythagorean Theorem say ?say ?
A.A. xx22 + y + y22 = 13 = 13
B.B. 2x2x22 + y + y22 = 169 = 169
C.C. xx22 + 2y + 2y22 =13 =13
D.D. xx22 + y + y22 = 169 = 169
What does the What does the Pythagorean Theorem Pythagorean Theorem say?say?
A.A. xx22 + y + y22 = 13 = 13
B.B. 2x2x22 + y + y22 = 169 = 169
C.C. xx22 + 2y + 2y22 =13 =13
D.D. xx22 + y + y22 = 169 = 169
Related RatesRelated RatesWrite an equationWrite an equation
Differentiate the equationDifferentiate the equation
implicitlyimplicitly
2x x’ + 2y y’ = 0 or xx’ + yy’ = 02x x’ + 2y y’ = 0 or xx’ + yy’ = 0
If Joe pulls at 2 ft./sec., find the If Joe pulls at 2 ft./sec., find the speedspeed
of the painter when x = 5.of the painter when x = 5.
2 2 213x y
Find y when x = 5Find y when x = 5
A.A. 55
B.B. 88
C.C. 1212
D.D. 1313
2 2 213x y
Find y when x = 5Find y when x = 5
A.A. 55
B.B. 88
C.C. 1212
D.D. 1313
2 2 213x y
Related RatesRelated RatesUse algebra to find y.Use algebra to find y.
xx22 + y + y22 = 169 = 169
5522 + y + y22 = 169 = 169
yy22 = 169 – 25 = 144 = 169 – 25 = 144
y = 12y = 12
2x x’ + 2y y’ = 0 or 2x x’ + 2y y’ = 0 or xx’ + yy’ = 0xx’ + yy’ = 0Back to the calculus with y = 12,Back to the calculus with y = 12,
x = 5, and x’ = 2 ft/secx = 5, and x’ = 2 ft/sec
xx’ + yy’ =0xx’ + yy’ =0
5(2) + 12(y’) = 05(2) + 12(y’) = 0
y’ = -10/12 = -5/6 ft./sec.y’ = -10/12 = -5/6 ft./sec.
2 2 213x y
Related RatesRelated RatesSummarySummary
Even though Joe is walking 2 ft/sec,Even though Joe is walking 2 ft/sec,
the painter is only falling -5/6 the painter is only falling -5/6 ft/sec. ft/sec.
If the x and y values were If the x and y values were reversed,reversed,
xx’ + yy’ =0 Find xx’ + yy’ =0 Find y’ if x’=2, y=5, and x = y’ if x’=2, y=5, and x = 1212A.A. -24/5-24/5
B.B. 5/245/24
C.C. -5/24-5/24
D.D. -5-5
xx’ + yy’ =0 Find xx’ + yy’ =0 Find y’ if x’=2, y=5, and x = y’ if x’=2, y=5, and x = 1212A.A. -24/5-24/5
B.B. 5/245/24
C.C. -5/24-5/24
D.D. -5-5
Related RatesRelated RatesSummarySummary
0lim ' ? when 5 ' 0yy x yy
0
5limy
x
y
0
5lim ? since x is approaching 13y
x
y
Related RatesRelated Rates
Suppose air is entering a balloon at Suppose air is entering a balloon at the rate of 25 cubic feet per the rate of 25 cubic feet per minute. How fast is the radius minute. How fast is the radius changing when r = 30 feet?changing when r = 30 feet?
Related RatesRelated Rates
r’ = 0.00221r’ = 0.00221
ft per minft per min
34
3v r
24dv dr
rdt dt
225 4 30dr
dt
25
4 900
dr
dt
Related RatesRelated Rates
Suppose a 6 ft tall person walks Suppose a 6 ft tall person walks away from a 13 ft lamp post at a away from a 13 ft lamp post at a speed of 5 ft per sec. How fast is speed of 5 ft per sec. How fast is the tip of his shadow moving when the tip of his shadow moving when 12 ft from the post? 12 ft from the post?
6
s
Related RatesRelated Rates
Suppose a 6 ft tall person walks Suppose a 6 ft tall person walks away from a 13 ft lamp post at a away from a 13 ft lamp post at a speed of 5 ft per sec. How fast is speed of 5 ft per sec. How fast is the tip of his shadow moving when the tip of his shadow moving when 12 ft from the post? 12 ft from the post?
6 13
s
Find ?Find ?
A.A. ss
B.B. xx
C.C. s + xs + x
D.D. 33
6 13
?s
Find ?Find ?
A.A. ss
B.B. xx
C.C. s + xs + x
D.D. 33
6 13
?s
Related RatesRelated Rates
The tip of the shadow has a speed The tip of the shadow has a speed of of
(s+x)’, not s’. What is s’ ?(s+x)’, not s’. What is s’ ?
s’ is the growth of the shadow and s’ is the growth of the shadow and includes getting shorter on the includes getting shorter on the right.right.6 13
s s x
Related RatesRelated Rates
The tip of the shadow has a speed The tip of the shadow has a speed of of
(s+x)’, not s’. What is s’ ?(s+x)’, not s’. What is s’ ?
s’ is the growth of the shadow and s’ is the growth of the shadow and includes getting shorter on the includes getting shorter on the right.right.
Cross multiplyingCross multiplying
6 13
s s x
6( ) 13s x s
Cross multiplyingCross multiplying
6( ) 13s x s 6 6 13s x s
Cross multiplyingCross multiplying
Since x’ = 5Since x’ = 5
6( ) 13s x s 6 6 13
6 7
6 ' 7 '
s x s
x s
x s
7 '5
6'
s
s
Related RatesRelated Rates
Thus s’ isThus s’ is
andand
Note that the tip is moving almostNote that the tip is moving almost
twice as fast as the walker, and more twice as fast as the walker, and more than twice as fast as the shadow than twice as fast as the shadow regardless of x.regardless of x.
30'7
s 30 65' ' 5
7 7s x
Related RatesRelated RatesSuppose a radar gun on first base Suppose a radar gun on first base catches a baseball 30 feet away catches a baseball 30 feet away from the pitcher and registers 50 from the pitcher and registers 50 feet per second. How fast is the feet per second. How fast is the ball really traveling?ball really traveling?
a baseball 30 feet away a baseball 30 feet away from the pitcher and from the pitcher and registers 50 registers 50 . feet per . feet per second.second.
A.A. x=30 y’=50x=30 y’=50
B.B. x=30 y =50x=30 y =50
C.C. x’=30 y’=50x’=30 y’=50
D.D. x’=30 y=50x’=30 y=50
Related RatesRelated Rates
The calculus.The calculus.
x = 30 y’ = 50 y = ?x = 30 y’ = 50 y = ?
The algebra.The algebra.
2 2 22 45 x y
2 ' 2 'xx yy
2 2 22 45 30 y
4950 y
DifferentiateDifferentiateimplicitlyimplicitly
A.A. 2x = 2y y’2x = 2y y’
B.B. 2x = y y’2x = y y’
C.C. 2x x’ = y y’2x x’ = y y’
D.D. 2x x’ = 2y y’2x x’ = 2y y’
2 2 22 45 x y
DifferentiateDifferentiateimplicitlyimplicitly
A.A. 2x = 2y y’2x = 2y y’
B.B. 2x = y y’2x = y y’
C.C. 2x x’ = y y’2x x’ = y y’
D.D. 2x x’ = 2y y’2x x’ = 2y y’
2 2 22 45 x y
Related RatesRelated Ratesx = 30 y’ = 50 y = ?x = 30 y’ = 50 y = ?
Back to the calculus.Back to the calculus.
2 ' 2 'xx yy
4950 y
2(30) 'x
Related RatesRelated RatesBack to the calculus.Back to the calculus.
x = 30 y’ = 50 y = ?x = 30 y’ = 50 y = ?
2 ' 2 'xx yy4950 y
2(30) ' 2 4950 'x y
Related RatesRelated RatesBack to the calculus.Back to the calculus.
x = 30 y’ = 50 y = ?x = 30 y’ = 50 y = ?
2 ' 2 'xx yy4950 y
2(30) ' 2 4950(50)x
a baseball 30 feet away a baseball 30 feet away from the pitcher and from the pitcher and registers 50 registers 50 . feet per . feet per second.second.A.A. x’ = 0.6 root(4950)x’ = 0.6 root(4950)
B.B. x’ = 50 root(4950)x’ = 50 root(4950)
C.C. x’ = 30 root(4950)x’ = 30 root(4950)
D.D. x’ = 5/3 root(4950)x’ = 5/3 root(4950)
2 ' 2 4950 'xx y
a baseball 30 feet away a baseball 30 feet away from the pitcher and from the pitcher and registers 50 registers 50 . feet per . feet per second.second.A.A. x’ = 0.6 root(4950)x’ = 0.6 root(4950)
B.B. x’ = 50 root(4950)x’ = 50 root(4950)
C.C. x’ = 30 root(4950)x’ = 30 root(4950)
D.D. x’ = 5/3 root(4950)x’ = 5/3 root(4950)
2 ' 2 4950 'xx y
Related RatesRelated Ratesx’ = 117.260 feet/sec.x’ = 117.260 feet/sec.
X = 30 y’ = 50 y = ?X = 30 y’ = 50 y = ?
2 ' 2 'xx yy 4950 y
4950(50)'
30x
2(30) ' 2 4950(50)x
Related RatesRelated RatesRead the problem, drawing a pictureRead the problem, drawing a picture
No non-constants on the pictureNo non-constants on the picture
Write an equationWrite an equation
Differentiate implicitlyDifferentiate implicitly
Enter non-constants and solveEnter non-constants and solve