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The function y = f ( x ) is defined by x = 2t - | t |, y = t2 + t | t |, t ∈ R in the interval x ϵ [ - 1, 1 ] then
Consider the function f ( x ) = x - | x - x2 |, - 1 ≤ x ≤ 2. The points of discontinuities of f ( x ) for x ∈ [ - 1, 2 ] are
Suppose ' f ' is continuous function from R to R and f ( f ( a ) ) = a for some a ∈ R then the equation f ( x ) = x has
If f ( a ) = a, then obviously x = a is the solution
Let f ( a ) > a and g ( x ) = f ( x ) - x
then g ( a ) > 0 and
g ( f ( a ) ) = f ( f ( a ) ) - f ( a ) = a - f ( a ) < 0
Since g(x) is continuous, so at least for one
c ∈ ( a, f ( a ) ), g ( c ) = 0.
Similarly we can argue for f ( a ) < a.
The correct answer is: at least three solutions
Let f ( x ) be a continuous function ∀ x ∈ R, f ( 0 ) = 1 and f ( x ) ≠ x for any x ∈ R then
Let g ( x ) = f ( x ) - x, so g ( x ) is continuous and g ( 0 ) = 1.
Now it is given that g ( x ) ≠ 0 for any x ∈ R so,
g ( x ) > 0 ∀ x ∈ R
i.e., f ( x ) > x ∀ x ∈ R
⇒ f ( f ( x ) ) > f ( x ) > x ∀ x ∈ R.
The correct answer is: f ( f ( x ) ) > x ∀ x ∈ R
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