`1+costheta+cos2theta`

If (2^n+1)theta=pi then 2^n costheta cos2theta cos2^2 theta .......cos 2^(n-1) theta=

Solve the following equation: costheta\ cos2theta\ cos3theta=1/4

If y=1costheta+2cos2theta+3cos3theta++99 cos 99theta , the maximum value of y is 5490 b. 4950 c. 9450 d. oo

Show that costheta [[costheta, sintheta],[-sintheta, cos theta]] + sin theta [[sintheta ,-cos theta],[costheta, sin theta]] =1

Show that costheta [[costheta, sintheta],[-sintheta, cos theta]] + sin theta [[sintheta ,-cos theta],[costheta, sin theta]] =1

4costheta cos 2theta cos3theta - 2cos 4theta=1

The minimum value of cos2theta +costheta for all values of theta is :

Prove that: (cos6theta+6cos4theta+15 cos2theta+10)/(cos5theta+5cos3theta+10 costheta)=2costheta