`cos^(2)theta+sin^(2)theta`

If cos^(2)theta+2sin^(2)theta+3cos^(2)theta+4sin^(2)theta+......20terms=10025 and theta is an acute angle then the value of sin theta-cos theta is

If 2cos^(2)theta-2sin^(2)theta=1, then theta is equal to

If 2cos^(2)theta-2sin^(2)theta=1, then theta equals to

Simplify cos^2theta-sin^2theta

Prove the following identity: ((1)/(sec^(2)theta-cos^(2)theta)+(1)/(cos ec^(2)theta-sin^(2)theta))sin^(2)theta cos^(2)theta=(1-sin^(2)theta cos^(2)theta)/(2+sin^(2)cos^(2)theta)

If cos2 theta=2sin^(2)theta then theta

Prove that 1-cos^2theta-sin^2theta=0

The value of theta lying between 0 and pi/2 and satisfying the equation |(1+cos^2theta, sin^2theta, 4sin4theta),(cos^2theta, 1+sin^2theta, 4sin4theta),(cos^2theta, sin^2theta, 1+4sin4theta)|=0 is (are) (A) (7pi)/24 (B) (3pi)/8 (C) (11pi)/24 (D) (7pi)/12