If $\tan \theta + \sec \theta = {e^x},$ then $\cos \theta $ equals
$\frac{{({e^x} + {e^{ - x}})}}{2}$
$\frac{2}{{({e^x} + {e^{ - x}})}}$
$\frac{{({e^x} - {e^{ - x}})}}{2}$
$\frac{{({e^x} - {e^{ - x}})}}{{({e^x} + {e^{ - x}})}}$
Prove that $\cos \left(\frac{3 \pi}{4}+x\right)-\cos \left(\frac{3 \pi}{4}-x\right)=-\sqrt{2} \sin x$
The value of $\cot \frac{\pi}{24}$ is :
The value of $\sin 10^\circ + \sin 20^\circ + \sin 30^\circ + ... + $ $\sin 360^\circ $ is
If $\sin x=-\frac{3}{5}$, where $\pi < x < \frac{3 \pi}{2}$ then $80\left(\tan ^2 x-\cos x\right)$ is equal to :
Find the values of other five trigonometric functions if $\sec x=\frac{13}{5}, x$ lies in fourth quadrant.