Question

The function f(x)=x+cosx is
(a) Always increasing
(c) Increasing for certain range of x
(b) Always decreasing
(d) None of these​

Answer 1

Answer:

It's too simple dear....

Learn theories first then try problem solving....

Actually if f '(x) >=0 then function is increasing.....

Also your function is

--> X + cosX

f '(x) = 1 - sinX

Since -1 <sinX< 1

So 0 < f '(x) = 1 - sinX < 2

Which is always positive

So f(x) = X + cosX is always increasing.....