The profit function of a firm is differentiable and attains a local maximum at units

MATHEMATICS · Subjective · AP · Calculus AB · Analytical Applications of Differentiation · Analytical Applications of Differentiation

Problem

The profit function

P(x)

of a firm is differentiable and attains a local maximum at

x=150

units. What must be the value of

P'(150)

? Give reason in one sentence.