If and are continuous on and differentiable on

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

Problem

If f(x)f(x) and g(x)g(x) are continuous on [a,b][a,b] and differentiable on (a,b)(a,b), prove that there exists c∈(a,b)c\in(a,b) such that ∣f(a)f(b)g(a)g(b)∣=(b−a)∣f(a)f′(c)g(a)g′(c)∣.\left|\begin{array}{cc}f(a)&f(b)\\g(a)&g(b)\end{array}\right|=(b-a)\left|\begin{array}{cc}f(a)&f'(c)\\g(a)&g'(c)\end{array}\right|.

Related theory

Browse the problem library