Thursday

August 28, 2014

August 28, 2014

Posted by **nic** on Tuesday, January 25, 2011 at 10:30pm.

y = 5x3 - 6x.

y=? ...............i keep getting y=x+2 and its wrong. can someone please help?

- calculus -
**MathMate**, Tuesday, January 25, 2011 at 11:34pmLet f(x)=5x³-6x, then

f(-1)=5(-1)³-6(-1)=1

Slope at (x, f(x)) is given by dy/dx=f'(x)

f'(x) = dy/dx = 15x³-6

f'(-1)= 15(-1)²-6=9

Therefore you need a line with a slope of 9 to pass through the point (-1,1).

The standard equation for this is:

(y-y1)=m(x-x1)

where m=9, y1=-1, x1=1

(y-(-1)) = 9(x-1)

y=9x-9-1

y=9x-10 (slope of 9 and passes through (-1,1))

**Related Questions**

calculus - Consider the curve defined by 2y^3+6X^2(y)- 12x^2 +6y=1 . a. Show ...

Calculus - Please help this is due tomorrow and I dont know how to Ive missed a ...

Calculus - Damon - Find the line which passes through the point (0, 1/4) and is ...

Calculus - If F(x)=x^3−7x+5, use the limit definition of the derivative to...

calculus - Consider line segments which are tangent to a point on the right half...

calculus - Consider line segments which are tangent to a point on the right half...

please help; calc - original curve: 2y^3+6(x^2)y-12x^2+6y=1 dy/dx=(4x-2xy)/(x^2+...

calculus - Consider the curve given by the equation y^3+3x^2y+13=0 a.find dy/dx...

Calculus - Consider line segments which are tangent to a point on the right ...

12th Grade Calculus - 1. a.) Find an equation for the line perpendicular to the ...