Posted by **A.L** on Sunday, March 25, 2012 at 3:06am.

2cos^2a*cos^2b+2sin^2asin^2b-1=cos2acos2b how to prove it,please help me

## Answer this Question

## Related Questions

- maths - 2cos^2a*cos^2b+2sin^2asin^2b-1=cos2acos2b
- math - 2cos^2a*cos^2b+2sin^asin^b-1=cos2acos2b how to prove it
- Math - Solving Trig Equations - What am I doing wrong? Equation: sin2x = 2cos2x ...
- Math - Which expression is equivalent to sin(3x) + sin x? A) 2cos(2x)sin x B) ...
- math - the problem is 2cos^2x + sinx-1=0 the directions are to "use an identity ...
- Math - Trig - Double Angles - Prove: cos4x = 8cos^4x - 8cos^2x + 1 My Attempt: ...
- Math, derivatives - f(x) = x² + 2Cos²x, find f ' (x) a) 2(x+cos x) b) x - sin x ...
- Calc - Which expression is equivalent to sin(3x) + sin x? A. 2cos(2x)sin x B. ...
- Calc - Which functions of x and y in terms of time t can be derived from this ...
- Pre-calc/Calc - Which expression is equivalent to sin(3x) + sin x? A. 2cos(2x)...