Check the injectivity and surjectivity of the following functions:

1) f:N-N given by f(x) = x^2
2) f:Z-Z given by f(x) = x^2
3) f:R-R given by f(x) = x^2
4) f:N-N given by f(x) = x^3
5) f:Z-Z given by f(x) = x^3

How do I know if its surjective or injective? please help?

Question

Check the injectivity and surjectivity of the following functions:

1) f:N->N given by f(x) = x^2
2) f:Z->Z given by f(x) = x^2
3) f:R->R given by f(x) = x^2
4) f:N->N given by f(x) = x^3
5) f:Z->Z given by f(x) = x^3

How do I know if its surjective or injective? please help?

anonymous · Answer

@ganeshie8 could you please help me out? I have a test at 2:30 pm and this is one of my last few topics to finish(its 12:42PM now!!)

ganeshie8 · Answer

injecttive is same as one to one :  each girl has exactly one boyfriend, and no boy has more than 1 girlfriend.

ganeshie8 · Answer

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ganeshie8 · Answer

the line is injective, because each y coordinate has only one x coordinate

anonymous · Answer

How'd you make that graph? Am I missing out on a key concept?

ganeshie8 · Answer

the curve is NOT injective, because the same y has two x coordinates

ganeshie8 · Answer

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