Let f : R R be a function such that f(x)+3f ( 2-x )= x, x R. Let the maximum value of f on R be . If the area of the region bounded by the curves g(x)=x2 and h(x)= x3, >0, is 2, then 30 3 is equal to .
Answer
16
Solution
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Given f(x)+3f ( 2-x )= x …(i); replacing x by 2-x: f ( 2-x )+3f(x)= x …(ii)
3 (ii) − (i): 8f(x)=3 x- x f(x)= 3 x- x8
= 32+128= 108 2= 1064= 532
x2= x3 x=0 or x= 1 ; for 0<x< 1 , x2> x3
Area = 01/ (x2- x3 )dx= 13 3- 14 3= 112 3
112 3= 532 3= 3260= 815
30 3=16
Answer: 16