Show that`cos^2(pi/4-x)+cos^2(pi/4+x)=1`

If sinx+sin^2x=1 then show that cos^2 x +cos^4 x=1

cos((3pi)/4+x)-cos((3pi)/4-x)=

Prove the following: cos(pi/4+x)+cos(pi/4-x)=sqrt2cosx

Select and write the correct answer from the given alternatives in each of the following: cos(3pi/4+x)-cos(3pi/4-x) =………

cos^2(pi/12)+cos^2(pi/4)+cos^2((5pi)/12)=

Prove the following: cos(pi/4-x).cos(pi/4-y)-sin(pi/4-x).sin(pi/4-y)=sin(x+y)

Prove the following: 4cosxcos(pi/3+x)cos(pi/3-x)=cos3x

Prove the following: cos(pi/2-x)cos(pi/2-y)-sin(pi/2-x)sin(pi/2-y)=-cos(x+y)

The number of solutions of the equation cos^2(x+pi/6)+cos^2x-2cos(x+pi/6)dotcos(pi/6)=sin^2(pi/6) in interval ((-pi)/2,pi/2) is_________

cos(pi/7)cos((2pi)/7)cos((4pi)/7)=