I found a math assuming fog(x)=f(g(x)), f"(x)=fof^(n-1)(x), fog^2012(x)=0.
What do they mean actually? Please describe in a way that I understand.
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$\begingroup$$(f$ o $g)(x)$ is the concatenation of two functions. It is described by the first equation$$(f \text{ o } g)(x)=f(g(x))$$
As an example: If $f(x)=x^2$ and $g(x)=2x$ then$$(f \text{ o } g)(x)=f(g(x))=f(2x)=(2x)^2=4x^2$$
In other words, you use the function value of the inner function as new argument for the outer function and evaluate there.
The other two equations seem strange. They are probably just true for this exercise and you need to work with it further. But with the knowledge of the concatenation, hopefully now its clearer what they mean. :)
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