I am so lost. Prove the Identity. Sin 2x sec x= 2 sin x & Sin x= sin 2x/2 cos x
L Leopard111 New member Joined Mar 14, 2010 Messages 4 Mar 14, 2010 #1 I am so lost. Prove the Identity. Sin 2x sec x= 2 sin x & Sin x= sin 2x/2 cos x
mmm4444bot Super Moderator Joined Oct 6, 2005 Messages 10,962 Mar 14, 2010 #2 ? Do you understand that you're trying to show how one side (or both), can be transformed into the other? Start by writing the secant term using a fundamental identity for secant: sec(x) = 1/cos(x) After you replace sec(x) with 1/cos(x), look at the double-angle identity for sine. sin(2x) = 2 sin(x) cos(x) After you replace sin(2x) with 2 sin(x) cos(x), reduce the ratio by canceling common factors. Questions? ?
? Do you understand that you're trying to show how one side (or both), can be transformed into the other? Start by writing the secant term using a fundamental identity for secant: sec(x) = 1/cos(x) After you replace sec(x) with 1/cos(x), look at the double-angle identity for sine. sin(2x) = 2 sin(x) cos(x) After you replace sin(2x) with 2 sin(x) cos(x), reduce the ratio by canceling common factors. Questions? ?