Question

Let `"f (x) = x – cos x, x" in "R"`, then f is ____________.

विकल्प

• a decreasing function

• none of these

• an odd function

• an increasing function

Answer 1

Let `"f (x) = x – cos x, x" in "R"`, then f is an increasing function.

Explanation:

`"f'" ("x") = 1 + "sin x" ge 0 AA  "x" in "R".`

`(because - 1 le "sin x" le 1, therefore 0 le 1 + "sin x" le 2)`

Hence an increasing function.