an equation of the line tangent to the graph of f(x)=x(1-2x)^3 at the point (1,-1) is
a) y=-7x+6
b) y=-6x+5
c) y= -2x
d) y= 2x-3
e) y=7x-8

Question

an equation of the line tangent to the graph of f(x)=x(1-2x)^3 at the point (1,-1) is 
a) y=-7x+6
b) y=-6x+5
c) y= -2x
d) y= 2x-3
e) y=7x-8

solomonzelman · Answer

1) Take the derivative of the function.
2) Plug in the x-coordinate into the derivative to solve for the slope.
3) then knowing you point (1,-1) and the slope,
and using the point slope formula, find the equation.

anonymous · Answer

yeah i did that but i wasn't sure how to change the equation from (y-y1)=m(x-x1)  to the way the formula looks on the list of choices

solomonzelman · Answer

can you show me how you take the derivative.
(For this I would expand, and not use the product rule + the chain rule for the second composite function)

solomonzelman · Answer

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