D.P. GUPTA, Preetima Bajpai and, Sanjeev Kumar Jha Solutions for Chapter: Trigonometric Functions, Exercise 1: Exercise 1

In a $\mathrm{\Delta }ABC$, if $\tan \frac{A}{2}=\frac{5}{6},\tan \frac{C}{2}=\frac{2}{5}$, then

In a triangle $ABC, \frac{a\cos A+b\cos B+c\cos C}{a+b+c}$ is equal to

If in $∆ABC$ the line joining the circumcentre and the incentre is parallel to $BC$, then

If $\sin \left(y+z-x\right), \sin \left(z+x-y\right)$ and $\sin \left(x+y-z\right)$ are in $\mathrm{A}.\mathrm{P}.$ (with $x, y, z\ne \frac{\mathrm{\pi }}{2}$), then $\tan x, \tan y$ and $\tan z$ are in

If $2y\cos \theta =x\sin \theta$ and $2x\sec \theta -ycosec\theta =3,$ then $x^2+4y^2=$

In a $\mathrm{\Delta }ABC\mathit{,}$ if $a=13, b=14$ and $c=15$, then the value of $\sin \left(\frac{A}{2}\right)$ is

If $\cos 2B=\frac{\cos \left(A+C\right)}{\cos \left(A-C\right)},$ then $\tan A, \tan B \& \tan C$ are in

If $n=\frac{\pi }{4\alpha },$ then $\tan \alpha \tan 2a\tan 3\alpha ....\tan \left(2n-1\right)\alpha$ is equal to