MCQ
The minimum value of function $f(x) = 3{x^4} - 8{x^3} + 12{x^2} - 48x + 25$ on $[0, 3] $ is equal to
- A$25$
- ✓$-39$
- C$-25$
- D$39$
$\therefore$ $f'(x) = 12{x^3} - 24{x^2} + 24x - 48$
$ = 12[{x^3} - 2{x^2} + 2x - 4]$$ = 12[(x - 2)({x^2} + 2)]$
For maximum and minimum value of the function$f'(x) = 0$
==> $x = 2$. Now $f''(x) = 12[3{x^2} - 4x + 2]$
$\therefore$ $f''(2) = 12\,[12 - 8 + 2] = 72 > 0$
Hence the function is minimum at $x = 2$
Minimum value of $f(x)$on $ [0, 3]$
$ = \min \left\{ {f(0),\,f(2),\,f(3)} \right\}$
$ = \min \left\{ {25,\, - 39,\,16} \right\}$$ = - 39$.
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| List $I$ | List $II$ |
| $P.$ The number of polynomials $f(x)$ with non-negative integer coefficients of degree $\leq 2$, satisfying $f(0)=0$ and $\int_0^1 f(x) d x=1$, is | $1.$ $8$ |
| $Q.$ The number of points in the interval $\mid-\sqrt{13}, \sqrt{13})$ at which $f(x)=\sin \left(x^2\right)+\cos \left(x^2\right)$ attains its maximum value, is | $2.$ $2$ |
| $R.$ $\int_{-2}^2 \frac{3 x^2}{\left(1+e^x\right)} d x$ equals | $3.$ $4$ |
| $S.$ $\frac{\left(\int_{-1 / 2}^{1 / 2} \cos 2 x \log \left(\frac{1+x}{1-x}\right) d x\right)}{\left(\int_0^{1 / 2} \cos 2 x \log \left(\frac{1+x}{1-x}\right) d x\right)}$ equals | $4.$ $0$ |
Codes: $ \quad P \quad Q \quad R \quad S$