How do you verify the identity cosx+cosxtan^2x=secx?

1 Answer
Nov 14, 2016

Use the following identities:

$\tan \theta = \sin \frac{\theta}{\cos} \theta$
$\sec \theta = \frac{1}{\cos} \theta$

$\cos x + \cos x \times {\sin}^{2} \frac{x}{\cos} ^ 2 x = \frac{1}{\cos} x$

$\cos x + {\sin}^{2} \frac{x}{\cos} x = \frac{1}{\cos} x$

$\frac{{\cos}^{2} x + {\sin}^{2} x}{\cos} x = \frac{1}{\cos} x$

Use the identity ${\sin}^{2} \theta + {\cos}^{2} \theta = 1$.

$\frac{1}{\cos} x = \frac{1}{\cos} x$

$L H S = R H S$

Hopefully this helps!