Calculus Examples

$lim_{x \to 0} \frac{\sin (4 x)}{\tan (3 x)}$

Step 1

Apply trigonometric identities.

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Step 1.1

Rewrite $\tan (3 x)$ in terms of sines and cosines.

$lim_{x \to 0} \frac{\sin (4 x)}{\frac{\sin (3 x)}{\cos (3 x)}}$

Step 1.2

Multiply by the reciprocal of the fraction to divide by $\frac{\sin (3 x)}{\cos (3 x)}$ .

$lim_{x \to 0} \frac{\sin (4 x) \cos (3 x)}{\sin (3 x)}$

Step 1.3

Convert from $\frac{\sin (4 x) \cos (3 x)}{\sin (3 x)}$ to $\sin (4 x) \cot (3 x)$ .

$lim_{x \to 0} \sin (4 x) \cot (3 x)$

Step 2

Consider the left sided limit.

$lim_{x \to 0^{-}} \sin (4 x) \cot (3 x)$

Step 3

Make a table to show the behavior of the function $\sin (4 x) \cot (3 x)$ as $x$ approaches $0$ from the left.

$\begin{array}{c} x & \sin (4 x) \cot (3 x) \\ - 0.1 & 1.25888363 \\ - 0.01 & 1.33257788 \\ - 0.001 & 1.33332577 \end{array}$

Step 4

As the $x$ values approach $0$ , the function values approach $1.333$ . Thus, the limit of $\sin (4 x) \cot (3 x)$ as $x$ approaches $0$ from the left is $1.333$ .

$1.333$

Step 5

Consider the right sided limit.

$lim_{x \to 0^{+}} \sin (4 x) \cot (3 x)$

Step 6

Make a table to show the behavior of the function $\sin (4 x) \cot (3 x)$ as $x$ approaches $0$ from the right.

$\begin{array}{c} x & \sin (4 x) \cot (3 x) \\ 0.1 & 1.25888363 \\ 0.01 & 1.33257788 \\ 0.001 & 1.33332577 \end{array}$

Step 7

As the $x$ values approach $0$ , the function values approach $1.333$ . Thus, the limit of $\sin (4 x) \cot (3 x)$ as $x$ approaches $0$ from the right is $1.333$ .

$1.333$