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fk378
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Homework Statement
Find the tangent line and the normal line to the curve y=(1+2x)^2 at the point (1,9).
Homework Equations
f'(x)= [f(x+h) - f(x)] / h ->plug in x=1
f'(x)= [f(x+h) - f(x)] / h ->plug in (x+h)
Power Rule
Power Rule (after factoring out the polynomial)
The Attempt at a Solution
I tried to solve it 4 different ways using the above 4 different approaches:
Plugging in x=1 for the derivative formula yields 12
Plugging in (x+h) for the derivative formula yields 4+8x
Using the power rule for (1+2x)^2 = 2(1+2x) = 2+4x (simplified version of 4+8x)
Using the power rule after factoring out the polynomial is 1+4x+4x^2 = 4+8xRegarding the first attempt, I thought I could plug in the x-coordinate to get the tangent equation. Since when is that wrong?
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