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Let f :[1,oo] to[2,oo]differentiable function such that f (1) = 2 .If [1,oo] to[2,oo]

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Solution :Given , f `(1)=(1)/(3)and6 int_(1)^(x)f(t)dt = 3xf (x) -x^(3),AAx le 1`Using Newton - Leibnitz formula. Differentiating both sides
`rArr6(x)*1-0=3f(x)+3xf'(x)-3x^(2)`
`RARR 3xf' (x) -3 f(x) = 3x^(2) rArr f' (x) -(1)/(x)f(x)=x`
`rArr (xf'(x)-f'(x))/(x^(2))=1rArr (d)/(dx){(x)/(x)}=1`
On INTEGRATING both sides , we get
`rArr (f(x))/(x')=x+c`"" [`:' f(1)=(1)/(3)]`
`(1)/(3)=1+crArrc=(2)/(3)ANDF(x)=x^(2)-(2)/(3)x`
`:. f(2)=4-(4)/(3)=(8)/(3)`
NOTEHere , f (1) = 2 , does not satisfy given function.
`:. f(1) = (1)/(3)`
For that f (x)`=x^(2)-(2)/(3)x andf(2)=4-(4)/(3)=(8)/(3)`


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