  ### Home > CALC > Chapter 7 > Lesson 7.4.2 > Problem7-190

7-190.

No Calculator! Evaluate the following limits.

1. $\lim\limits_ { x \rightarrow 0 } \frac { \operatorname { sin } x ^ { 2 } } { x ^ { 2 } }$

$\text{This is an indeterminate form: }\frac{0}{0}.$
Use l'Hopital's Rule.

1. $\lim\limits_ { x \rightarrow \infty } \frac { 100 x + 40 x ^ { 2 } - 5 x ^ { 3 } } { 10 x ^ { 3 } + 50 x ^ { 2 } - 100 }$

This is a limit $→ ∞$.
Compare the powers on the top and bottom only.
Do not neglect their coefficients.

1. $\lim\limits _ { x \rightarrow \pi ^ { + } } \operatorname { csc } x$

$\text{csc}x=\frac{1}{\text{sin}x}\text{ and sin}\pi =0.$
So this limit must be approaching $+∞$ or $−∞$.
Which one?

1. $\lim\limits_ { h \rightarrow 0 } \frac { e ^ { 2 + h } - e ^ { 2 } } { h }$

This is Hana's Definition of the Derivative.
The limit is equal to $f^\prime(2)$ when $f(x) = e^x$.

1. $\lim\limits_ { x \rightarrow \infty } \frac { e ^ { x } + x ^ { 3 } } { e ^ { x } + x ^ { 2 } }$

This is a limit $→ ∞$. Be careful. Which is more powerful: an exponential function or a polynomial function? 