SOLUTION: What is the maximum y value of V(x)=x(x-10)(x-8)

Algebra.Com
Question 697551: What is the maximum y value of V(x)=x(x-10)(x-8)
Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
What is the maximum y value of V(x)=x(x-10)(x-8)
-----------
V(x) = x^3 - 18x^2 + 80x
V'(x) = 3x^2 - 36x + 80 = 0
Solved by pluggable solver: SOLVE quadratic equation (work shown, graph etc)
Quadratic equation (in our case ) has the following solutons:



For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=336 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: 9.05505046330389, 2.94494953669611. Here's your graph:

----------------
-----------
V''(x) = 6x - 36
--> inflection at x = 6
--> local max @ x2, 2.9449...
max = V(x2) =~ 105.0276

RELATED QUESTIONS

If u + v + w + x + y = 15, then what is the maximum value of uvx + uvy + uwx +... (answered by ikleyn)
If x and y are positive integers such that x=8, what is the maximum possible value of... (answered by Alan3354)
what is the maximum value of... (answered by Alan3354)
For y=8+2x-x^2, what is the maximum value of y? Thankyou in... (answered by checkley77)
I dont understand what they are looking for An open-top box is to be constructed from... (answered by checkley75)
X-U (-1, 3) Y-E (µ) V(X)=V(Y) What is the value of µ... (answered by ikleyn)
what is the maximum value of... (answered by josmiceli)
What is the maximum and minimum value value of y=2sin(x)+2 and what are the corresponding (answered by stanbon)
What is the maximum y value on the graph of y = 4cos(x - 20) +... (answered by Fombitz)