Find the Limit of a Function Practice Test

Solve the limit as approaches infinity.

$\lim_{x\rightarrow \infty }\frac{3x^4-2^7x^2+4x}{5x^2-13x^4+5x}$

Calculate $\lim_{x\rightarrow \infty }\left( x^{2} \sin \frac{1}{ x^{2}-1} - \sin \frac{1}{ x^{2}-1} \right)$.