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This problem is killing me:

y = x^3 - 3x^2 + 4 P(2,0)

Find the slope of the curve at P and the equation of the tangent line at P.

Any help PLEASE, i'm dying from this...............................................................

2007-01-17 03:29:40 · 6 answers · asked by AppleCard! 2 in Science & Mathematics Mathematics

6 answers

Take the derivative:

y' = 3x² - 6x

Evaluate it at x = 2:

y'(2) = 3(2)² - 6(2) = 0

So the slope of the tangent line will be 0:

y - 0 = 0(x - 2)

Which results in the horizontal line:

y = 0

2007-01-17 03:35:10 · answer #1 · answered by Jim Burnell 6 · 0 0

To find slope of a curve find it's derivative. In this case U need to know that the derivative of the "x ^ n" is "n * (x ^ n-1)". So the derivative of the y = x^3 - 3x^2 + 4 is
dy/dx = 3 * (x ^ 2) - 6 * x

slope of the curve can be found by substituting x=2 to the above equation. (because x coordiante of the p is 2)

slope = 0

equation of the tangent line at P is y=0 because slope is 0.

2007-01-17 03:51:21 · answer #2 · answered by Mahesh U 2 · 0 0

The slope is the value of the derivative at the point
y´= 3x^2 -6x = 3*4-6*2 =0
the tangent is horizontal
eq. y=0

2007-01-17 03:39:10 · answer #3 · answered by santmann2002 7 · 0 0

dy/dx = 3x^2 - 6x

m(2,0) = 3*2^2 - 6*2 = 0

0 = 0*2 + b
b=0

y=0 is the tangent

2007-01-17 03:38:14 · answer #4 · answered by gebobs 6 · 0 0

take the derivative, y' = 3x^2 - 6x

plug in P(2,0)

Answer: 0

(the slope is horizontal at this point)

2007-01-17 03:33:53 · answer #5 · answered by Anonymous · 1 0

dy/dx = (3x^2 - 6x)
therefore slope at (2,0) =dy/dx at (2,0)
slope = 0
it means equation of x axis i.e. y = 0

2007-01-17 04:52:24 · answer #6 · answered by Laeeq 2 · 0 0

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