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The number of points in (-oo,oo), for wh...

The number of points in `(-oo,oo),` for which `x^2-xsinx-cosx=0,` is 6 (b) 4 (c) 2 (d) 0

A

6

B

4

C

2

D

0

Text Solution

Verified by Experts

The correct Answer is:
3
Let f(x) =`x^(2)-xsin x-cos x`
`therefore f(X)=2x-xcosx`
`f(X)=0 rarr x(2-cosx)=0 or x=0`
Also x-=0 is point of minima
`f(0)=-1lt0and underset(xrarroo)limf(X)rarroo,underset(xrarr-oo)limf(X)rarroo`

Hence it meets x axis at two points and hence two solutons
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