Posted by **Christine** on Sunday, August 2, 2009 at 7:21pm.

a) determine the equation of the line that is perpendicular to the tangent to y=5x^2 at (1,5).

b) determine the equation of the line that passes through (2,2) and is parallel to the line tangent to y=-3x^3-2x at (-1,5).

- Math -
**MathMate**, Sunday, August 2, 2009 at 9:59pm
(a)

y=5x²

dy/dx=5*2x=10x, slope of tangent

slope of line perpendicular to tangent

= -1/(10x)

At (1,5), slope of perpendicular line

= -1/(10*1) = -1/10

Line passing through (1,5)

(y-5)=-(1/10)(x-1)

y =-(1/10)x + 5.10

Test for perpendicularity at (1,5)

-(1/10) * (10*1)

= -1 Line and tangent are perpendicular.

(b) y=-3x^3-2x at (-1,5).

dy/dx = -9x² -2 = -9-2 = -11 at (-1,5)

Slope of tangent = -11

Line passing through (2,2) with slope of -11

(y-2) = -11(x-2)

y-2 = -11x + 22

y = -11x + 24

- Math -
**deon**, Tuesday, April 5, 2011 at 5:16pm
slope of -8y-3x+5=10x

## Answer This Question

## Related Questions

- Analytic Geometry - A line Q has an equation of x+5x+5=0. Find the equation of ...
- Analytic Geometry - A line Q has an equation of x+5y+5=0. Find the equation of ...
- Pre-Calculus - Determine the equation of a line that passes through (2,2) and is...
- Algebra 1 - Write an equation in slope-intercept form for a line that passes ...
- MAT221 - consider the line 8x-5y=-4 find the equation of the line that is ...
- Math- finding equation - Can someone explain to me how to find the equation pf ...
- math - a) Determine an equation for the line with slope 3 and passing through ...
- Math 10 - 1 more question.... how would I make this equation perpendicular? The ...
- precalc - write a linear equation to fit each situation or description. 1) the ...
- Algebra II - Can you make sure my Algebra II work is correct? I've done the ...

More Related Questions