prove for x?
回答 (1)
2015-01-07 11:01 pm
f(0) = 0
f '(x) = cos(x) + 2 > 0 , f(x) is an increasing function , hence f(x)>0 for x in (0,infinity)
f '(x) = cos(x) + 2 > 0 , f(x) is an increasing function , hence f(x)>0 for x in (0,infinity)
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