calculus problem -sending out a SOS

[gongshow]

The deflection y of a beam of length L at a horizontal distance x from
one end is given by: y = K(2x^4 -5Lx^3 +3L^2x^2) where K is a constant.
For what value of X does the maximum occur?

 

[stapel]

To find the maximum value of this function, take the first derivative, set it equal to zero, and find the critical points. Then either compare to the graph, or else check the signs on the intervals, or else use the Second Derivative Test, to find the critical point which is the maximum you seek.

If you get stuck or are unsure of your answer, please reply showing all of your steps.

Thank you.

Eliz.

 

[gongshow]

iS this right

y= k(8x^3 -15Lx^2 +6L^2
0= k(x) (8x^2 - 15Lx + 6L^2)
0= 8x^2 -15Lx + 6L^2