![](http://admin.getprephub.com/media/editor/te13_20230123200629024584.png) Find $$\cos 2<B A C$$

Answer Let,$$< B A C=\theta$$ Since, $$\cos 2 \theta=2 \cos ^{2} \theta-1$$ Now, $$\cos \theta=\frac{A C}{A B}=\frac{\text{Adjacent Leg length}}{\text{Hyppotenuse}}=\frac{3}{5}$$ Putting the value, $$\cos 2 \theta=2(\frac{3}{5})^{2}-1=\frac{18}{25}-1=-\frac{7}{25}$$

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MCQ

Find $\cos 2<B A C$

Select all that apply :

$-\frac{7}{25}$

$\frac{7}{25}$

$-\frac{7}{5}$

$-\frac{5}{27}$

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