Question

Trig help

Answer 1

The goal is to rewrite acos(@)+bcos(@) as a cosine function with amplitude A. Start by multiplying and dividing a and b in acos(@)+bcos(@) by A expressed in terms of a and b:


acos(@)+bcos(@)=



Factor out A:


acos(@)+bcos(@)=


Write the coefficients in front of cost and sint as two trigonometric functions of angle@. The coefficient in front of cost should be cosine and the coefficient in front of sint should be sine:


cos(@)=

sin(@)=






Using the cosine of the difference formula from Unit 2 Lesson 10, rewrite the resulting expression as a single cosine:


acos(@)+bcos(@)=







Record the expressions for A, sin(@),cos(@) , and tan(@) in terms of a and b.

Answer 2

I think I would understand it except the first bit confuses me.