The local extrema of f(x) = x + 2*sin(x) are 6.2832 and 2.4567 (approx).
If the question was about some other function of x, please resubmit using words for mathematical symbols. The browser that you are required to use for posting questions is rubbish and will reject most mathematical symbols. In this case, all that I can see is "f(x)x 2sinx" and have had to guess the rest.