Target Exam

CUET

Subject

-- Applied Mathematics - Section B2

Chapter

Calculus

Question:

Find the maximum and the minimum values (if any) of the function $f(x) = 2x^3 +5$.

Options:

Maximum value: 5; Minimum value: None

Maximum value: None; Minimum value: 5

Both maximum and minimum values exist.

Neither a maximum nor a minimum value exists.

Correct Answer:

Neither a maximum nor a minimum value exists.

Explanation:

The correct answer is Option (4) → Neither a maximum nor a minimum value exists.

Given $f(x) = 2x^3 +5, D_f= R$.

Now when $x → ∞, f(x) → ∞$ and when $x → -∞, f(x) → -∞$.

Therefore, $f$ has neither maxima nor minima.

In fact, f is a strictly increasing function for all $x∈R$.