Sorry if I posted this in the wrong place.
Two numbers x and y are such that 2x + y = 12.
The product P is formed by multiplying the first number by the square of the second number so that P = xy²
P = 4x³ - 48x² + 144x
I worked out the two values of x for which dP/dx = 0
They are x = 6 and x = 2 (hopefully!)
Now it says : The values of x and y must both be positive, show that there is only one value of x for which P is stationary.
How do I do this?
Please and thank you x