Prove that sin `(theta)/(2) sin"" (7 theta)/(2) + sin ""(3theta)/(2) sin ""(11 theta)/(2) = sin 2theta sin5 theta`.

sin""(theta )/(2)* sin""(7 theta )/(2) + sin""(3theta )/(2) * sin""(11 theta )/(2) - sin 2 theta sin 5 theta =

Prove that sin((theta)/(2))sin((7 theta)/(2))+sin((3 theta)/(2))sin((11 theta)/(2))=sin2 theta sin5 theta

sin ((theta) / (2)) sin ((7 theta) / (2)) + sin ((3 theta) / (2)) sin ((11 theta) / (2)) = sin (2 theta) sin (5 theta)

Let f_(n)(theta)= 2 sin . (theta)/(2) sin. (3theta)/(2) + 2 sin.(theta)/(2) sin. (5theta)/(2) + 2sin. (theta)/(2) sin. (7 theta)/(2) + ... + 2 sin (2 n+1) (theta)/(2), n in N , then which of the following is/are correct ?

Let f_(n)(theta)= 2 sin . (theta)/(2) sin. (3theta)/(2) + 2 sin.(theta)/(2) sin. (5theta)/(2) + 2sin. (theta)/(2) sin. (7 theta)/(2) + ... + 2 sin (2 n+1) (theta)/(2), n in N , then which of the following is/are correct ?

Let f_(n)(theta)= 2 sin . (theta)/(2) sin. (3theta)/(2) + 2 sin.(theta)/(2) sin. (5theta)/(2) + 2sin. (theta)/(2) sin. (7 theta)/(2) + ... + 2 sin (2 n+1) (theta)/(2), n in N , then which of the following is/are correct ?

Prove that: 4sin theta sin(theta+(pi)/(3))sin(theta+(2 pi)/(3))=sin3 theta

If theta = (pi)/(21) , then (sin23 theta-sin 7 theta)/( sin2 theta + sin 14 theta)=

Prove that , sin theta + sin 2theta + ……+ sin n theta = ( (sin( n theta/(2)) sin ((n+1)/(2))theta))/(sin theta/2) , for all n in N .

Prove that : (sin theta + 2 sin 3theta + sin 5theta)/(sin 3theta + 2 sin 5theta + sin 7theta) = (sin 3theta)/(sin 5theta)