Matematica CBC

$\left [ \left ( \frac{1}{5} \right )^3 \left (\frac{1}{5}  \right )^4\right ]^\frac{2}{7}$
$\left [ \left (\frac{1}{5}  \right )^7\right ]^\frac{2}{7}$
$\left (\frac{1}{5}  \right )^\left ( 7* \frac{2}{7}\right )$
$\left (\frac{1}{5} \right )^2$
$\frac{1}{25}$

Trigonometria

26
a.
$\sin{2x}\tan{x}+\cos{2x}=1$
$2\sin{x}\cos{x}\frac{\sin{x}}{\cos{x}}+\cos^2{x}-\sin^2{x} = 1$
$\sin^2{x} +\cos^2{x} = 1 $
1=1
b.

$\sin{2x}\sin{x}+2\cos^3{x}= 2\cos{x}$
$2\sin{x}\cos{x}\sin{x}+ 2\cos^2{x}\cos{x}$
$2\sin^2{x}\cos{x}+ 2\cos^2{x}\cos{x}$
$2\cos{x}[\sin^2{x}+ \cos^2{x}]$
$2\cos{x}$=$2\cos{x}$