### Home > PC > Chapter 4 > Lesson 4.1.2 > Problem 4-29

You can use the image of a BOW TIE to remind you to always draw a vertical line to the*x*-axis when completing a triangle to compute sine and cosine. This is because the triangle you work with will always be part of the bow tie. Homework Help ✎

In the diagram, assume the bow tie is symmetric with respect to both coordinate axes. Let*α*= ∠EOW,*β*= ∠EOB,*γ*= ∠EOT, and*δ*= ∠EOI, where all of these angles are in standard position and between 0 and 2. The angles for α and*β*are shown. Assume sin*α*=. Without finding

*α*, find the*exact*values for sin*β*, sin*γ*, and sin*δ*.Use the Fundamental Pythagorean Identity or a right triangle to find cos

*α*.Find the

*exact*values for cos*β*, cos*γ*, and cos*δ*.

The first two are negative cosθ.

The last one is positive cosθ.