I need to prove f(f^-1(Y'))[itex]\subseteq[/itex]Y' for some f: X -> Y and Y' in Y.(adsbygoogle = window.adsbygoogle || []).push({});

So far, I've been able to figure this much out:

Let y[itex]\in[/itex]f(f^-1(Y')). Then, f^-1(Y') = x' for some x' in X such that f(x') = y' for some y' in Y'. Then, f(x') = y'. Thus, f(f^-1(Y'))[itex]\subseteq[/itex]Y'.

I feel like there's something wrong with my proof. Any ideas on where I went wrong?

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# Set function proof

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