Determine the tangent line of f(x)=(x−1)(x2−4) at x=−1.

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Lesson Parent: 
The Formula of the Tangent Line
Problem: 

Determine the tangent line of f(x)=(x−1)(x2−4) at x=−1.

Answer: 

y=x+7

SAMPLE SOLUTION

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Solution: 

We know that the general formula for the tangent line at a point xo for f(x) is

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In this problem <Sign in to see all the formulas>. So <Sign in to see all the formulas>. We have already found that

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So <Sign in to see all the formulas>.

Therefore, the formula for the tangent line at x=−1 is

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