1.

Let `f(x)=3x^2-7x+c ,`where `c`is a variable coefficient and `x >7/6`. Then the value of `[c]`such that `f(x)`touches `f^(-1)(x)`is (where [.] represents greatest integer function)_________

Answer» Correct Answer - 5
`f(x) and f^(-1)(x)` can only intersect on the line `y=x` and therefore, `y=x` must be tangent at the common point of tangency. Hence,
` 3x^(2)-7x+c=x`
` or 3x^(2) -8x+c=0 " (1)" `
This equation must have equal roots. Therefore,
`64-12c =0`
`or c=(64)/(12)=(16)/(3)`


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