Stitz-Zeager_College_Algebra_e-book

The tree is about 47 feet tall 7 the lights are about

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: gles. In the table below, we summarize the values which we consider essential and must be memorized. Cosine and Sine Values of Common Angles θ(degrees) θ(radians) 0◦ 0 30◦ π 6 π 4 π 3 π 2 45◦ 60◦ 90◦ cos(θ) sin(θ) 1 0 3 2 √ 2 2 1 2 1 2 √ 2 2 √ 3 2 0 1 √ Example 10.2.3. Find the cosine and sine of the following angles. 1. θ = 225◦ 2. θ = 11π 6 π 3. θ = − 54 4. θ = 7π 3 Solution. 1. We begin by plotting θ = 225◦ in standard position and find its terminal side overshoots the negative x-axis to land in Quadrant III. Hence, we obtain θ’s reference angle α by subtracting: α = θ − 180◦ = 225◦ − 180◦ = 45◦ . Since θ is a Quadrant III angle, both cos(θ) < 0 and sin(θ) < 0. Coupling this with the Reference Angle Theorem, we obtain: cos (225◦ ) = √ √ − cos (45◦ ) = − 22 and sin (225◦ ) = − sin (45◦ ) = − 22 . 618 Foundations of Trigonometry 2. The terminal side of θ = 11π , when plotted in standard position, lies in Quadrant IV, just shy 6 of the positive x-axis. To find θ’s reference angl...
View Full Document

This note was uploaded on 05/03/2013 for the course MATH Algebra taught by Professor Wong during the Fall '13 term at Chicago Academy High School.

Ask a homework question - tutors are online