Let $f: R→ R$ be defined as $f(x)=4x^2-16x+5,$ then
A. Maximum value of f(x) is -11.
B. Minimum value of f(x) is -11.
C. Minimum value of f(x) is 20.
D. No maximum value of f(x).
Choose the correct answer from the options given below
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → B and D only
$f: R→ R,f(x)=4x^2-16x+5$
It''s critical point is, $f'(c)=0$
$⇒8c-16=0$
$⇒c=2$
Now, for $x=2$ to be minima, $f''(x)>0$
$⇒f''(2)=8>0$
∴ at $x=2$, $f(x)$ has minima
$f(2)=4(2)^2-16(2)+5$
$=-11$
and,
thus it has no maxima value.