661d[f(x)]dx=3x2+5,>0 for all values of x.
therefore,f(x) is increasing over R so it is one-one also f(-∞)=-∞
and f(∞)=∞ so f(x) tkes all values between -∞ and ∞
therefore f(x) is one-one and onto R
For real x, let f(x)=x3 +5x+1, then prove that f is one-one and onto R.
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