Question

If the function f(x) = 2x² + 3x + 5 satisfies LMVT at x = 3 on

the closed interval [1, a] then the value of 'a' is equal to

• A. 3
• B. 4
• C. 5
• D. 1

Answer 1

Answer: (C)

5

Answer 2

f ¢(3) = $\frac{f(a) - f(1)}{a - 1}$ Ž $\frac{2a^{2} + 3a - 5}{a - 1}$ = 15

Ž a² – 6a + 5 = 0 Ž a = 5