Continuity — Question 8

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Question 8

Let f(x)={sin⁡(3x)x,x≠0c,x=0f(x) = \begin{cases} \frac{\sin(3x)}{x}, & x \neq 0 \\ c, & x = 0 \end{cases}

Find the value of cc that makes f(x)f(x) continuous at x=0x = 0.

Original worksheet page 1: question and worked solution for 2-9-008
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Question 8 - Solution

To ensure continuity at x=0x = 0, we require: limx→0f(x)=f(0)=c\lim_{x \to 0} f(x) = f(0) = c

Compute the limit: limx→0sin⁡(3x)x=limx→03sin⁡(3x)3x=3⋅limx→0sin⁡(3x)3x=3⋅1=3\lim_{x \to 0} \frac{\sin(3x)}{x} = \lim_{x \to 0} \frac{3\sin(3x)}{3x} = 3 \cdot \lim_{x \to 0} \frac{\sin(3x)}{3x} = 3 \cdot 1 = 3

Thus, to make ff continuous at x=0x = 0, we must set: c=3\boxed{c = 3}

Original worksheet page 2: question and worked solution for 2-9-008

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