EQUATION MAY be written as \[\frac{2}{\cos 2\alpha }=\frac{\SIN \beta }{\cos \beta }+\frac{\cos \beta }{\sin \beta }=\frac{{{\sin }^{2}}\beta +{{\cos }^{2}}\beta }{\cos \beta \sin \beta }\]\[=\frac{1}{\cos \beta .\sin \beta }\] Þ \[\cos 2\alpha =\sin 2\beta \] Þ \[\cos 2\alpha \]= \[\cos \,\left( \frac{\pi }{2}-2\beta\right)\]Þ \[2\alpha =\frac{\pi }{2}-2\beta \]Þ Þ .