Let $f: R→R$ be defined such that $f(x) = 16x^2 -16x+12 $ (A) Maximum value of f(x) is 8 (B) Minimum value of f(x) is 8 (C) Minimum value of f(x) is 16 (D) No maximum value of f(x) Choose the correct answer from the options given below : |
(A), (C) Only (B), (D) Only (A), (B), (C) Only (A), (B) Only |
(B), (D) Only |
The correct answer is Option (2) → (B), (D) Only $f(x)=16x^2-16x+12$ $⇒f'(x)=32x-16$ for critical points, $(32x-16)=0$ $x=\frac{16}{32}=\frac{1}{2}$ Now, $f''(x)=32>0$ ∴ f only has minima $f(\frac{1}{2})=16(\frac{1}{2})-16(\frac{1}{2})+12$ $=8$ |