`1+costheta+cos2theta`

Find the sum of the series costheta- (cos2theta)/(2!)+(cos3theta)/(3!)-… to oo

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

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

The possible value of theta in [-pi, pi] satisfying the equation 2(costheta + cos 2theta)+ (1+2costheta)sin 2theta = 2sintheta are

if costheta+cos2theta+cos3theta=0 , the general value of theta is

Find the general value of theta from the equation costheta+cos2theta + cos3theta=0 .

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

Find (dy)/(dx) , if x=costheta-cos2theta , y=sintheta-sin2theta