જો $\cos \left( {\alpha + \beta } \right) = \frac{4}{5}$ અને $\sin \left( {\alpha - \beta } \right) = \frac{5}{{13}}$,કે જ્યાં $0 \le \alpha ,\beta \le \frac{\pi }{4}$. તો $\tan 2\alpha $ મેળવો.
$\frac{{16}}{{63}}$
$\frac{{56}}{{33}}$
$\frac{{28}}{{33}}$
એકપણ નહિ.
$\frac{{\sec 8A - 1}}{{\sec 4A - 1}} = $
$4 \,\,sin5^o \,\,sin55^o \,\,sin65^o$ =
જો $A + B + C = \pi ,$ તો ${\tan ^2}\frac{A}{2} + {\tan ^2}\frac{B}{2} + $${\tan ^2}\frac{C}{2}$ એ . . ..
જો $A + B + C = \frac{{3\pi }}{2},$ તો $\cos 2A + \cos 2B + \cos 2C = $
$\cos \frac{\pi }{5}\cos \frac{{2\pi }}{5}\cos \frac{{4\pi }}{5}\cos \frac{{8\pi }}{5} = $