Let
A--------> the corner point in the graph

B--------> the corner point in the graph

C--------> the corner point in the graph

D--------> the corner point in the graph

we know that
The function P is equal to

Step

Evaluate the function P in each corner point
point


point


point


point


the maximum value of P is for the point C

therefore
the answer is
The maximum value of the function P is
