Question

if tanA=4/3,then find the value of cos2A​

Answer 1

Answer:

tanA=$\frac{4}{3}$

we have to find cos2A​,

so the formula of cos2A​=$cos^{2}$A-$sin^{2}$A

tanA=$\frac{4}{3}$=$\frac{opposite}{adjecent}$

Sin A=$\frac{4}{5}$

Cos A=$\frac{3}{5}$

NOW,

cos2A​=$cos^{2}$A-$sin^{2}$A

=$(\frac{3}{5})^2$-$(\frac{4}{5})^2$

=$\frac{9}{25}$-$\frac{16}{25}$

$\frac{-7}{25}$

Thank you