Application of DerivativeHard
Question
If y = a log x + bx2 + x has its extremum values at x = -1 and x = 2, than
Options
A.a = 2,b = - 1
B.a = 2, b = - 
C.a = - 2, b =
D.None of these
Solution
y = a log x + bx2 + x has extremum at x = - 1 and x = 2
∴
= 0, x = - 1 and x = 2
⇒
+ 2bx + 1 = 0, at x = - 1and x = 2
∴ - a - 2b + 1 = 0 and
+ 4b + 1 = 0
⇒ a = 2 and b = -
∴
= 0, x = - 1 and x = 2⇒
+ 2bx + 1 = 0, at x = - 1and x = 2∴ - a - 2b + 1 = 0 and
+ 4b + 1 = 0 ⇒ a = 2 and b = -
Create a free account to view solution
View Solution FreeMore Application of Derivative Questions
The equation of the tangent to the curve 6y = 7 - x3 at point (1, 1) is -...If f(x) = (x - 4) (x - 5) (x - 6) (x - 7) then,...The lines tangent to the curves y3 - x2y + 5y - 2x =0and x4 - x3y2 + 5x + 2y = 0 at the origin intersect at an angle f(x...If the polynomial equation anxn + an−1xn−1 + ... + a2x2 + a1x + a0 = 0 n positive integer, has two different...A particle begins at the origin and moves successively in the following manner as shown, 1unit to the right, 1/2 unit up...