For real x, let f(x) = x^3 + 5x + 1, then

• Relations Functions

For real x, let f(x) = x³ + 5x + 1, then

1. f is one-one and onto R
2. f is onto R but not one-one
3. f is neither one-one nor onto R
4. f is one-one but not onto R

Solution

f(x) = x³ + 5x + 1

f'(x) = 3x² + 5

So, f is one-one.

The correct option is D.