Question #a681a

1 Answer
Mar 20, 2017

The minimum value of the above is -1.5, which occurs when x = -1.5

Explanation:

To find out the maximum or minimum, first differentiate the function with respect to x and equate it to 0. As you may know, the differential coefficient of a function represents the slope of the tangent of the function. So when the function reaches a maximum or minimum value, its slope is 0. That is the reason why we differentiate it and equate it to 0. In this case, df(x) / dx = 4x + 6. Equating this to 0, we get 4x + 6 = 0 or x = -1.5. Substituting it in the original function, we get f(-1.5) = 2(1.5)2+6(1.5)+3=22.259+3=4.59+3=4.5+3=1.5. Also, d2f(x)dx2=4. Since this is positive, what we have calculated is the minimum value. If d2f(x)dx2 had been negative, what we have calculated as per the above procedure is the maximum value of the function.