Thursday

September 18, 2014

September 18, 2014

Posted by **Kate** on Monday, July 18, 2011 at 11:30am.

a) 1-cos^2x=tan^2xcos^2x

b) cos^2x + 2sin^2x-1 = sin^2x

I also tried a question on my own:

tan^2x = (1 – cos^2x)/cos^2x

R.S.= sin^2x/cos^2x

I know that the Pythagorean for that is sin^2x + cos^2x

That's all I could do.

- Math -
**MathMate**, Monday, July 18, 2011 at 11:42ama)

Given tan(θ)=sin(θ)/cos(θ)

substitute tan(θ) by sin(θ)/cos(θ) on the RHS and see what you get.

b) hint:

cos(2θ)=cos²(θ)-sin²(θ)

**Answer this Question**

**Related Questions**

Mathematics - Trigonometric Identities - Let y represent theta Prove: 1 + 1/tan^...

precalculus - For each of the following determine whether or not it is an ...

Trig - Given: cos u = 3/5; 0 < u < pi/2 cos v = 5/13; 3pi/2 < v < ...

Trigonometry desperate help, clueless girl here - 2. solve cos 2x-3sin x cos 2x...

Trigonometry - 1.Solve tan^2x + tan x – 1 = 0 for the principal value(s) to two ...

Pre-Calculus - I don't understand,please be clear! Prove that each equation is ...

Pre-Calculus - Prove that each equation is an identity. I tried to do the ...

MATH - Hi, I really need help with these questions. I did some of them halfway, ...

Math - Calculus - The identity below is significant because it relates 3 ...

calculus - Differentiate. y= (cos x)^x u= cos x du= -sin x dx ln y = ln(cos x)^x...