Maharashtra BoardEnglish MediumSTD 11 ScienceMathsFunctions2 Marks
MCQ
The equation $x^3+x-1=0$ has
A
no real root.
B
exactly two real roots.
✓
exactly one real roots.
D
more than two real roots.
✓
Answer
Correct option: C.
exactly one real roots.
(c) : $f(x)=x^3+x-1$ Now, $f(0)=0+0-1=-1<0$ and $f(1)=1+1-1=1>0$ So, $f(x)$ has a root in between 0 and 1 and $f^{\prime}(x)>0 \in R \forall$ $x>1 \therefore f(x)$ has exactly one real root.
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