how to prove that a given function is onto?

Hi!

Recall the definition,

A function

*f*:*X*→*Y*is said to be**onto**(or**surjective**) if every element of*Y*is the image of some element of*x*in*X*under*f*. In other words,*f*is onto if " for*y*∈*Y*, there exist*x*∈*X*such that*f*(*x*) =*y*.I.e.,

*f*:*X*→*Y*is onto if and only if the range of*f*=*Y*.So, in order to show that

*f*is onto; take any element (say*y*) of*Y*and than, check whether there exists*x*∈*X*such that*f*(*x*) =*y*.Hope! You got the required procedure.

Cheers!

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