Limits and Continuity

Evaluate the following limits:

a) lim⁡x→4x−4x−4\displaystyle \lim_{x \rightarrow 4} \frac{\sqrt{x} - \sqrt{4}}{x - 4}


b) lim⁡x→∞x2−5x+134x4+3x−21\displaystyle \lim_{x \rightarrow \infty} \frac{x^2 - 5x + 13}{\sqrt{4x^4 +3x - 21}}


c) lim⁡x→0sin⁡(3x)sin⁡(5x)sin⁡(x)sin⁡(8x)\displaystyle \lim_{x \rightarrow 0} \frac{\sin(3x) \sin(5x)}{ \sin(x) \sin(8x)}
More The Fundamental Trig Limit Questions:
More Computing Limits by Multiplying by the Conjugate Questions:
More Limits at Infinity Questions: