If `(cos^4A)/(cos^2B)+(sin^4A)/(sin^2B)=1` then prove that `(i)sin^4A+sin^4B=2sin^2Asin^2B` `(ii)(cos^4B)/(cos^2A)+(sin^4B)/(sin^2A)=1`

Prove that sin^2 A cos^2 B+cos^2 A sin^2 B+cos^2 A cos^2 B+sin^2 A sin^2 B=1

If (cos^(4)alpha)/(cos^(2) beta) + (sin^(4)alpha)/(sin^(2)beta) = 1, prove that (cos^(4)beta)/(cos^(2) alpha) + (sin^(4)beta)/(sin^(2)alpha)= 1

Prove that in a A B C ,sin^2A+sin^2B+sin^2C<=9/4dot

prove that a^2sin2B+b^2sin2A=4Delta

If (cos^(4)alpha)/(cos^(2) beta) + (sin^(4)alpha)/(sin^(2)beta) = 1, prove that sin^(4)alpha + sin^(4) beta = 2 sin^(2) alpha sin^(2) beta

Prove that sin ( A + B) sin (A - B) = sin^(2) A - sin^(2)B .

Prove that sin^(2)(A + B) - sin^(2)(A - B) = sin 2A sin 2B

Prove that sin 4A=4 sin A cos^(3) A-4 cos A sin^(3) A

Prove that (sinA+sin2A+sin4A+sin5A)/(cos A+cos2A+cos 4A+cos5A)=tan3A .

Solve the equation sin^4x+cos^4x-2sin^2x+(3sin^2 2x)/4=0