find the value of x for which the expression 2-3x-4x^2 has greatest value Share with your friends Share 0 Tanveer Sofi answered this The given expression is2-3x-4x2Let, fx=2-3x-4x2To find the maximum value of fx; we haveddxfx=ddx2-3x-4x2=-3-8x=-8x+3Also, d2dx2fx=d2dx2-8x+3=-8The critical points of fx are given byddxfx=0⇒-8x+3=0⇒x=-38Now, d2dx2fx=-8<0 for all real values of x. Therefore, x=-38 is the point of maximum value of fx. 5 View Full Answer
