Question

For all second degree polynomials with y = ax^2 + bx + k, it is seen that the Rolles’ point is at c = 0. Also the value of k is zero. Then what is the value of b?

(a) 0

(b) 1

(c) -1

(d) 56

The question was posed to me in homework.

The query is from Rolle’s Theorem in chapter Differential Calculus of Engineering Mathematics

Answer 1

The correct option is (a) 0

To explain: Given that k = 0 we must rewrite the function to get

y = ax^2 + bx

 Now differentiating the function yields

y’ = 2ax + b = 0

Equating it to zero we get the Rolle point which is also zero

2a(0) + b = 0

b = 0.