Tag: trigonometric identities

$Tan \,25^o.Tan \,31^o + Tan \,31^o.Tan \,34^o  + Tan \,34^o .Tan \,25^o =$

Let $x=\sin 1^{o}$, then the value of expression
$\dfrac {1}{\cos 0^{o}\cos 1^{o}}+\dfrac {1}{\cos 1^{o}\cos 2^{o}}+\dfrac {1}{\cos 2^{o}\cos 3^{o}}+....+\dfrac {1}{\cos 44^{o}\cos 45^{o}}=$

$\dfrac{\cos (45^0+A)-\cos(45^0-A)}{\sin(120^0+A)-\sin(120^0-A)}=?$

if $A=30$ then the value of $\cos 2A$ is

$(1+\tan 5^{o})(1+\tan 10^{o})(1+\tan 15^{o}).....(1+\tan 45^{o})$ is equal to

$sin 12^o\sin\ 24^o\sin\ 48^o\sin\ 84^o$=

$\tan 5\tan 25\tan 30\tan 65 \tan 85$ is equal to

$\tan 20 ^ { \circ } + \tan 40 ^ { \circ } + \sqrt { 3 } \tan 20 ^ { \circ } \tan 40 ^ { \circ }$  is equal to

If $\alpha =685^o$, then $(\cos\alpha -\sin\alpha)$ is equivalent to?

The distance between $A ( \cos \theta , \sin \theta )$ and $B ( - \sin \theta , \cos \theta )$ is