If `cos theta, sin phi, sin theta` are in G.P., then prove that roots of
`x^(2)+2 cot phi x+1=0` are real

Evaluate |[cos theta, -sin theta], [sin theta, cos theta]|

If A=[[cos theta, sin theta],[ -sin theta, cos theta]] , then prove that A^n=[[cos ntheta, sinn theta],[ -sin n theta, cos n theta]] , n in N .

If sin theta, cos theta are the roots of ax^(2)+bx+c=0 then prove that b^(2)=a^(2)+2ac

If x = a cos theta , y = b sin theta , then prove that ( d^(3) y)/( dx^(3)) = - ( 3 b)/( a^(3)) cosec^(4) theta cot theta

If cos (theta +phi)=m cos(theta-phi) ,then the value of (1-m)/(1+m)cot phi .

If cos theta+sin theta=sqrt(2) cos theta ,then show that cos theta-sin theta=sqrt(2) sin theta

The product of matrices A = [(cos^(2) theta, cos theta sin theta),(cos theta sin theta , sin^(2) theta)] and sin B = [(cos^(2)phi, cos phi sin phi),(cos phi sin phi, sin^(2) phi)] is a null matrix if theta - phi =

If the line joining the points (a cos theta , b sin theta) and (a cos phi, b sin phi) .Prove that the equation of this lines is x/a "cos" (theta + phi)/2 + y/b"sin" (theta + phi)/2 = "cos" (theta -phi)/2

Consider the equation sintheta+sin3theta+sin5theta=0 prove that sin3theta(1+2cos2theta)=0