(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Write the Trigonometric Expression as an algebraic expression.

cos(2arccos 2x)

2. Relevant equations

Probably the inverse properties, I'm not sure.

3. The attempt at a solution

I know I can rewrite this equation as.

u= arccos 2x

cos(2cos u=2x)

I can also say that the adjacent leg is 2x units long and the hypotenuse is 1 unit long. Then using the pythagorean theorm I can figure the opposite leg to be sqrt(1-4x^{2})

I'm not sure If this is necessary though can someone point me in the right direction? The 2 in front of the arccos is throwing me off because if that wasn't there I would just use the inverse property and cos(arccos 2x) would equal 2x.

**Physics Forums - The Fusion of Science and Community**

# Writing A Trig Expression as an Algebraic Expression

Know someone interested in this topic? Share a link to this question via email,
Google+,
Twitter, or
Facebook

Have something to add?

- Similar discussions for: Writing A Trig Expression as an Algebraic Expression

Loading...

**Physics Forums - The Fusion of Science and Community**