Post on 16-Dec-2015
transcript
LEARNING TARGETS
• AFTER YOU COMPLETE THIS CHAPTER, YOU WILL BE ABLE TO:
• DEFINE TRIGONOMETRIC RATIOS• CHANGE MEDIAN MEASURE TO DEGREE
MEASURE• DEFINE AND NAME TRIGONOMETRIC RATIOS IN
SPECIAL TRIANGLES• IDENTIFY GRAPHS OF SINE, COSINE, & TANGENT• USE THE LAW OF SINES AND COSINES
TRIGONOMETRY RATIOS
• Trigonometry: Comes from the Greek word, “trigonon” or triangle and “metron” to measure. The main part of trigonometry is the right triangle. There are several special names that define the ratios.
• Cosine, Sine, and Tangent.• They also have reciprocals (or the opposite)
Chapter Vocabulary
• Degree: 1/360 of a full circle – symbol = ⁰• Minute: 1/60 of a degree, so 1⁰ = 60’• Second: 1/60 of a minute, so 1’ = 60”• Quadrant – four parts of a circle, using Roman
Numerals and numbers counter-clockwise.• Quadrant I = 0⁰ to 90⁰• Quadrant II = 90⁰ to 180⁰• Quadrant III = 180⁰ to 270⁰• Quadrant IV = 270⁰ to 360⁰
What does this look like?
• Radians – the angle between two radii of a circle, which is cut off on the circumference by an arc equal in length to the radius.
Special Triangles
• 30 – 60 – 90 Triangle• 45 – 45 – 90 Triangle• There is a unique relationship to the sides in
these triangles:
Basic Identities
• Reciprocal – opposites• Pythagorean – using Pythagorean Theorem• Quotient – using division• Cofunction – one ratio working with another
The Unit Circle
• In the unit circle – the radius is 1. The right triangle for each quadrant is determined by the reference angle, the angle with the initial side at 0⁰.
Inverse Trigonometric Functions
• A quick look at the graph for cosine, sine, and tangent shows that there is one x and y value. They can pass the vertical line test. The inverse or opposite function cannot.
• Principal value: The value of a function in a restricted range.
• Arcsin, Arccos, Arctan are the inverse functions.
COFUNTCIONS AND COMPLEMENTARY ANGLES
• COFUNCTIONS OF COMPLETMENTARY ANGLES ARE EQUAL.
• COFUNTCION PAIRS:
SOLVING THE TRIANGLE
• Solving the triangle: the process to find the missing sides and angles.
• Law of Sines: