# Determining the equation of a line perpendicular to the tangent of y=2x-3x^3

• Feb 21st 2010, 04:35 PM
kmjt
Determining the equation of a line perpendicular to the tangent of y=2x-3x^3
Determine the equation of the line that passes through the point (2,2) and is perpendicular to the tangent to y=2x-3x^3 at x=-1.

To solve this first would I use the difference quotient on y=2x-3x^3 to find the slope of the tangent? And why can't I graph y=2x-3x^3 on my graphing calculator?
• Feb 21st 2010, 04:47 PM
skeeter
Quote:

Originally Posted by kmjt
Determine the equation of the line that passes through the point (2,2) and is perpendicular to the tangent to y=2x-3x^3 at x=-1.

To solve this first would I use the difference quotient on y=2x-3x^3 to find the slope of the tangent?

that would be a good start if you can't take the derivative directly using the power rule.

And why can't I graph y=2x-3x^3 on my graphing calculator?

what instructions were you given? is use of a calculator permitted for this problem?

...