" 9."sec((pi)/(4)+A)sec((pi)/(4)-A)=2sec2A

sec((pi)/(4)+theta)sec((pi)/(4)-theta)=2sec2 theta

Sec ((15pi)/4) =

The value of sec((pi)/(7))*sec(2(pi)/(7))*sec(3(pi)/(7)) is

int_((pi)/(4))^((pi)/(3))sec^(2)xdx

Let cos(pi)/(7),cos(3 pi)/(7),cos(5 pi)/(7) are the roots of equation 8x^(3)-4x^(2)-4x+1=0 Q.The value of sec((pi)/(7))+sec((3 pi)/(7))+sec((5 pi)/(7)) is

sec(pi/4+theta)sec(pi/4-theta)=2sec2theta

Prove that sec(pi/4+theta)sec(pi/4-theta)=2 sec 2theta

sec ((pi)/(4) + theta ) . Sec ((pi)/(4) - theta ) is equal to