Home › CBSE Class 12 › Mathematics › Relations and Functions › For f(x) = 2x from R to R, the function is:
For f(x) = 2x from R to R, the function is:
AOnly one-one, not onto
BOnly onto, not one-one
CNeither one-one nor onto
DBoth one-one and onto
Answer & Solution
Correct answer: D. Both one-one and onto
1. Doubling distinct reals gives distinct reals, so f is one-one.
2. Any real y is reached by taking x as half of y.
3. So over the reals the same rule is one-one and onto.
_Source: NCERT Class 12 Mathematics Part I, Chapter 1, Relations and Functions._
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