# Math Help - calc cubic formula

1. ## calc cubic formula

Find a formula for the following function.
A cubic polynomial with a local maximum at x = 3, a local minimum at x = 5, a y-intercept of 4, and an x3 term whose coefficient is 1.

does it get set up like x^3+ax^2+bx+4? then what?

2. Originally Posted by bluejewballs
Find a formula for the following function.
A cubic polynomial with a local maximum at x = 3, a local minimum at x = 5, a y-intercept of 4, and an x3 term whose coefficient is 1.

does it get set up like x^3+ax^2+bx+4? then what?
All of the stationary points (max, min, or saddle) occur when the deriviative is zero.

$y'=3x^2+2ax+b$
This should get you started.

Good luck.