The value of $\sum_{r-1}^{18} cos^2(5r)^o,$ where $x^o $ denotes the $x$ degree, is equals to
The value of $\sum_{r-1}^{18} cos^2(5r)^o,$ where $x^o $ denotes the $x$ degree, is equals to
- A
$\frac{19}{2}$
- B
$\frac{7}{2}$
- C
$\frac{17}{2}$
- D
$0$
Similar Questions
If a $cos^3 \alpha + 3a \,cos\, \alpha \, sin^2\, \alpha = m$ and $asin^3\, \alpha + 3a \, cos^2\, \alpha \,sin\, \alpha = n$ . Then $(m + n)^{2/3} + (m - n)^{2/3}$ is equal to :
If a $cos^3 \alpha + 3a \,cos\, \alpha \, sin^2\, \alpha = m$ and $asin^3\, \alpha + 3a \, cos^2\, \alpha \,sin\, \alpha = n$ . Then $(m + n)^{2/3} + (m - n)^{2/3}$ is equal to :
$\frac{{\tan A + \sec A - 1}}{{\tan A - \sec A + 1}} = $
$\frac{{\tan A + \sec A - 1}}{{\tan A - \sec A + 1}} = $
$\sqrt 2 + \sqrt 3 + \sqrt 4 + \sqrt 6 $ is equal to
$\sqrt 2 + \sqrt 3 + \sqrt 4 + \sqrt 6 $ is equal to
- [IIT 1975]
If $cos A = {3\over 4} , $ then $32\sin \left( {\frac{A}{2}} \right)\sin \left( {\frac{{5A}}{2}} \right) = $
If $cos A = {3\over 4} , $ then $32\sin \left( {\frac{A}{2}} \right)\sin \left( {\frac{{5A}}{2}} \right) = $
If $90^\circ < A < 180^\circ $ and $\sin A = \frac{4}{5},$ then $\tan \frac{A}{2}$ is equal to
If $90^\circ < A < 180^\circ $ and $\sin A = \frac{4}{5},$ then $\tan \frac{A}{2}$ is equal to