The number of real roots of equation X3 + X + lgx = 0 on (1.5) is? A0 B2 C1 D3
Because y = x ^ 3, y = x, y = lgx are all increasing functions in (1.5)
So f (x) = x ^ 3 + X + lgx is an increasing function in (1.5)
And because f (1) = 2 > 0
f(5)=130+lg5>0
So the equation x ^ 3 + X + lgx = 0 has no real root on (1.5)
So choose a
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