# Need help to Prove this

• Sep 21st 2012, 08:26 AM
kjchauhan
Need help to Prove this
If $\cos(\theta + i\phi)=\sec(\alpha + i\beta)$, then prove that $\tanh^{2}\phi\cosh^{2}\beta=\sin^{2}\alpha$ and $\tanh^{2}\beta\cosh^{2}\phi=\sin^{2}\theta$