MCQ
The maximum value of $2{x^3} - 24x + 107$ in the interval $[-3, 3]$ is
- A$75$
- B$89$
- C$125$
- ✓$139$
At $x = - 3,\;f( - 3) = 2{( - 3)^3} - 24( - 3) + 107 = 125$
At $x = 3,\;\;f(3) = 2{(3)^3} - 24(3) + 107 = 89$
For maxima or minima, $f'\,(x) = 6{x^2} - 24 = 0$
$ \Rightarrow x = 2,\;\; - 2$
So at $x = 2,\;f(2) = 2{(2)^3} - 24(2) + 107 = 75$
at $x = - 2,\;\;f( - 2) = 2{( - 2)^3} - 24( - 2) + 107 = 139$
Thus the maximum value of the given function in $ [-3, 3]$ is $139.$
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Maximize $z=2 x+3 y$ the coordinates of the corner points of the bounded feasible region are $A\,(3,3), B\,(20,3),$ $\mathrm{C}\,(20,10), \mathrm{D}\,(18,12)$ and $\mathrm{E}\,(12,12) .$ The maximum value of $z$ is $\ldots \ldots$