Posted by **Jake** on Monday, January 24, 2011 at 11:13pm.

An equation to the graph of y=x^3+3x^2+2 at its point of inflection is:

a) y=-3x+1

b)y=-3x-7

c)y=x+5

d)y=3x+1

e)y=3x+7

Please help. I am in urgent need.

- Math (Calculus AB) -
**MathMate**, Tuesday, January 25, 2011 at 12:27am
I suppose the question is:

"A *line tangent* to the graph of y=x^3+3x^2+2 at its point of inflection is"

First find the derivatives:

y' = 3x²+6x

y" = 6x+6

At the point of inflexion, y"=0, or x=-1.

Then the slope at x=-1 is

y'(-1) = 3-6=-3

There are only two choices of lines that have a slope of -3.

From these, we calculate

y(-1) = (-1)³+3(-1)²+2

=-1+3+2

=4

Which of these two lines (with slope = -3) gives y=4 at x=-1?

## Answer This Question

## Related Questions

- Calculus (Urgent Help) - Okay, I need major help! Can someone tell me if these ...
- Calculus - The number of people who donated to a certain organization between ...
- calculus ..>steve - Given a function f(x)2/3x^3+5/2x^2-3x. a) Find i. The ...
- calculus - the graph (x^5-15*x^3 +10) is sketched without axes and not to scale...
- calculus - let f be the function f(x) = x^3 + 3x^2 - x + 2 a. the tangent to the...
- Math(Please help) - 1) where is the function f(x)= 5 / (2x-4)^3 increasing. I ...
- calculus - 6. Determine a, b, c, and d so that the graph of y=ax^3+bx^2+cx+d has...
- AP Calculus - Suppose that f has a continuous second derivative for all x, and ...
- Calculus Need of Urgent help - find the indicated limits, if they exist. 1. lim...
- calculus - If the graph of f " (x) is continuous and has a relative maximum at x...

More Related Questions