Question 200746: find the relative maximum and relative minimum values of the function below.
f(x)=x^3+9x^2+15x-7
relative maximum: -5, _____
relative minimum: -1, ______
can not figure out the _____ part
can someone help please
thanks
Answer by RAY100(1637)   (Show Source):
You can put this solution on YOUR website! f(x) =y= x^3 +9x^2 +15x -7
.
differentiate
y' = 3 x^2 +18x +15
.
factor
(3x+3)(x+5)
x=-1,,,x=-5
.
Substitute into first eqn
,
y(-1) = (-1)^3 +9(-1)^2 +15(-1) -7
y(-1) = -1 +9 -15 - 7
y(-1) = - 14
.
y(-5) = (-5)^3 +9 (-5)^2 +15 (-5) -7
y(-5) = -125 +225 -75 -7
y(-5) = 18
.
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