The function f:(- , ) (- ,1), defined by f(x)= 2x-2-x2x+2-x is :
- One-one but not onto
- Onto but not one-one
- Both one-one and onto
- Neither one-one nor onto
Answer
(1) One-one but not onto
Solution
f(x)= 2x-2-x2x+2-x= 4x-14x+1=1- 24x+1
4x is increasing f is strictly increasing one-one
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As x - , f -1; as x , f 1 range =(-1,1)
Range codomain (- ,1) not onto
Answer: (1)