Saved Bookmarks
| 1. |
`L e tf(x)=x^3=(3x^2)/2+x+1/4`Then the value of `(int_(1/4)^(3/4)f(f(x))dx)^(-1)`os____ |
|
Answer» Correct Answer - 4 Given `f(x)=x^(3)-(3x^(2))/2+x+1/4=1/4(4x^(3)(4x^(3)-6x^(2)+4x+1)` `=1/4(4x^(3)-6x^(2)+4x-1+2)` `=1/4[x^(4)-(1-x)^(4)]+2/4` `:.f(1-x)=1/4[(1-x)^(4)-x^(4)]+2/4` `:.f(x)+f(1-x)=2/4+2/4=1` Replacing `x` by `f(x)`,...................1 we have `f[f(x)]+f[1-f(x)]=1`...............2 Now, `I=int_(1//4)^(3//4)f(f(x))dx`.............3 Also `I=int_(1//4)^(3//4)f(f(1-x))dx=int_(1//4)^(3//4) f(1-f(x))dx` [using 1 ] ...........4 Adding 3 and 4 we get `2I=int_(1//4)^(3//4)[f(f(x))+f(1-f(x))]dx=int_(1//4)^(3//4)dx=1/2` or `I=1/4` `:.I^(-1)=4` |
|