L’Hospital’s Rule and Indeterminate Forms — Question 1

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Question 1

Evaluate the limit: limx→0sin⁡(3x)x\lim_{x \to 0} \frac{\sin(3x)}{x}

(a) Verify that the limit results in an indeterminate form.

(b) Use L’Hospital’s Rule to evaluate the limit.

Original worksheet page 1: question and worked solution for 4-10-001
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Question 1 - Solution

(a) As x→0x \to 0:

- sin⁡(3x)→0\sin(3x) \to 0, and x→0x \to 0 - So, the limit is of the indeterminate form 00\frac{0}{0}

(b) Apply L’Hospital’s Rule:

limx→0sin⁡(3x)x=limx→0ddx[sin⁡(3x)]/ddx[x]\lim_{x \to 0} \frac{\sin(3x)}{x} = \lim_{x \to 0} \frac{d}{dx}[\sin(3x)] \Big/ \frac{d}{dx}[x]

=limx→03cos⁡(3x)1=3cos⁡(0)=3(1)=3= \lim_{x \to 0} \frac{3\cos(3x)}{1} = 3\cos(0) = 3(1) = \boxed{3}

Original worksheet page 2: question and worked solution for 4-10-001

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