If `sin^2theta-cos^2theta=1` then find the principal value of `theta`

If sin theta=-1, then the principal value of theta is

If sin theta+cos theta=sqrt(2), then the principal value of (theta+(pi)/(4)) is

If costheta+cos^(2)theta=1 , then find the value of sin^(4)theta+sin^(2)theta .

If sintheta+costheta=1/2 then find the value of 16(sin2theta+cos4theta+sin6theta)

If sintheta+sin^(2)theta=1 , then find the value of cos^(2)theta+cos^(4)theta .

If sin theta + cos theta = sqrt2 , then find the value of theta .

If sin^(2)theta-cos^(2)theta=(1)/(4) , then the value of (sin^(4)theta-cos^(4)theta) is :

If 1/(sin^(2)theta)-1/(cos^(2) theta)-1/(tan^(2)theta)-1/(cot^(2)theta)-1/(sec^(2)theta)-1/(cosec^(2)theta)=-3 then find the value of theta .

If 5sin^(2)theta+3cos^(2)theta=4 . Find the value of sin theta and cos theta :

If sin theta = cos theta , then find the value of 2 tan theta + cos^(2) theta .