how do i show that tangent squared 8x all divided by sin4x multiply by sin2x is equal to 8 and x gets closer to 0
huh? you are talking about limits here, right?
do you mean: $\displaystyle \lim_{x \to 0} \frac {\tan^2 8x}{\sin 4x \cdot \sin 2x}$ or $\displaystyle \lim_{x \to 0} \frac {\tan^2 8x}{\sin 4x} \cdot \sin 2x$ ?
it seems you mean the first.
Hint: multiply by $\displaystyle \frac {64x^2 \cdot 4x \cdot 2x}{64x^2 \cdot 4x \cdot 2x}$, rearrange and apply the limits according to the special limits you've learned $\displaystyle \left( \lim_{x \to 0} \frac {\sin x}x = 1 \text{ and } \lim_{x \to 0} \frac {\tan x}x = 1 \right)$