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5. Continuity and Differentiation
medium
જો વિધેય $f(x) =2x^3 + bx^2 + cx, x \in [-1, 1],$ એ બિંદુ $x = \frac {1}{2}$ આગળ રોલના પ્રમેયનું પાલન કરે તો $2b+ c=$
A
$-3$
B
$-1$
C
$2$
D
$1$
(JEE MAIN-2015)
Solution
Conduction for Rolls theorem
$f(1)=f(-1)$
and $f^{\prime}\left(\frac{1}{2}\right)=0$
$c=-2$ and $b=\frac{1}{2}$
$2 b+c=-1$
Standard 12
Mathematics