Dion S.

asked • 06/26/15

y = x3 - 3x + 4; x = 2

Find the equation of the tangent line to each curve at the given point.

2 Answers By Expert Tutors

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Selam N. answered • 06/26/15

Tutor
5 (6)

Mathematics Teacher

Dion S.

What formula did you use to come up with that answer could you please work it out for me for example y- y1 = m (x - x1) or y = mx + b
 
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06/26/15

Dion S.

Okay that makes sense.
 
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06/26/15

Dion S.

Im sorry one more question where did you get the 9 from in 6 = 9(2) + b the 6 makes sense 3(2) = 6 right but where did you get the 9.
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06/26/15

Selam N.

m, the slope is equal to dy/dx at any point x. However, to evaluate m when x=2, plug in 2 for x, 3(2)2 - 3=9. The slope, m=9 at x=2.

using the slope-intercept form of the eqn of a line, y=mx + b, where m=9, at the point of tangency, (2,6), solve for b, the y-intercept.

6=9(2) +b.

b =-12

 

 

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06/26/15

Dion S.

Find the derivative of each function.

y = 1/x-1
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06/28/15

Selam N.

dy/dx = d(x-1)/dx -d(1)/dx
         = -(x)-2
          =-(1/x)
 
However, if your question is, y = 1/(x-1)
dy/dx = [ d(1)/dx • (x-1) - (1)d(x-1)/dx]/(x-1)2
       Use the Quotient Rule
          =[0 -(1)]/(x-1)2
 
          =-1/(x-1)2
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06/28/15

Mark M. answered • 06/26/15

Tutor
5.0 (278)

Mathematics Teacher - NCLB Highly Qualified

Dion S.

Mr. Mark im having trouble with this Calculus problem can you help me we it.
 
Find the derivative of each function.

y = 1/x-1
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06/28/15

Dion S.

Thank You Mr Mark that makes sense.
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06/28/15

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