$2\,{\sin ^2}\beta + 4\,\,\cos \,(\alpha + \beta )\,\,\sin \,\alpha \,\sin \,\beta + \cos \,2\,(\alpha + \beta ) = $
$2\,{\sin ^2}\beta + 4\,\,\cos \,(\alpha + \beta )\,\,\sin \,\alpha \,\sin \,\beta + \cos \,2\,(\alpha + \beta ) = $
- [IIT 1977]
- A
$\sin \,\,2\alpha $
- B
$\cos \,\,2\beta $
- C
$\cos \,\,2\alpha $
- D
$\sin \,\,2\beta $
Similar Questions
If $k = \sin \frac{\pi }{{18}}\,.\,\sin \frac{{5\pi }}{{18}}\,.\,\sin \frac{{7\pi }}{{18}},$ then the numerical value of $k$ is
If $k = \sin \frac{\pi }{{18}}\,.\,\sin \frac{{5\pi }}{{18}}\,.\,\sin \frac{{7\pi }}{{18}},$ then the numerical value of $k$ is
- [IIT 1993]
$1 + \cos 2x + \cos 4x + \cos 6x = $
$1 + \cos 2x + \cos 4x + \cos 6x = $
જો $A$ એ ત્રીજા ચરણમાં હોય અને $3\,\tan A - 4 = 0,$ તો $5\,\sin 2A + 3\,\sin A + 4\,\cos A = $
જો $A$ એ ત્રીજા ચરણમાં હોય અને $3\,\tan A - 4 = 0,$ તો $5\,\sin 2A + 3\,\sin A + 4\,\cos A = $
$\sqrt 3 \, cosec\, 20^o - sec\, 20^o $ =
$\sqrt 3 \, cosec\, 20^o - sec\, 20^o $ =
$\frac{1}{{\sin 10^\circ }} - \frac{{\sqrt 3 }}{{\cos 10^\circ }} =$
$\frac{1}{{\sin 10^\circ }} - \frac{{\sqrt 3 }}{{\cos 10^\circ }} =$
- [IIT 1974]