Question

WILL GIVE BRAINLIEST!!! Given tan(theta) = 4/3 and pi < theta < (3pi)/2, find cos(2theta).

Answer 1

Answer:

answer d on edge

Step-by-step explanation:

the guy above got me

Answer 2

Answer:  $\cos 2 \theta = \dfrac{-7}{25}$

Step-by-step explanation:

Given: $\tan \theta = \dfrac{4}{3}$  and  $\pi < \theta< \dfrac{3\pi }{2}$

To find: $\cos 2 \theta$

Now as we know

$\cos 2x = \dfrac{1- \tan ^2 x}{1+ \tan ^2 x}$

So we have

$\cos 2 \theta = \dfrac{1-(\dfrac{4}{3} )^2}{1+(\dfrac{4}{3} )^2} \\\\\Rightarrow \cos 2 \theta = \dfrac{1- \dfrac{16}{9} }{1+ \dfrac{16}{9} } = \dfrac{\dfrac{9-16}{9} }{\dfrac{9+16}{9}} = \dfrac{-7}{25}$

Therefore d. is the correct option

Hence , $\cos 2 \theta = \dfrac{-7}{25}$