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Identifying the inverse - Solution

 y(t)=10^(log(t)), for 0.1<=t<5.01


Graph of  y(t)=10^(log(t)), for 0.1<=t<5.01 plotted by plotXpose, companion app with book,  Mathematics for Electrical Engineering and Computing

y(t)=sin(arcsin(t)) for -1<=t<1.01


y(t)=sin(arcsin(t)) for -1<=t<1.01  plotted by plotXpose, companion app with book,  Mathematics for Electrical Engineering and Computing


y(t)=tan(arctan(t)) for -10<=t<10.01


y(t)=tan(arctan(t)) for -10<=t<10.01  plotted by plotXpose, companion app with book,  Mathematics for Electrical Engineering and Computing


y(t)=(1/(1/t)) for 0.1<=t<10.01



y(t)=(1/(1/t)) for 0.1<=t<10.01  plotted by plotXpose, companion app with book,  Mathematics for Electrical Engineering and Computing


What do all the above graphs have in common and why?



All the above are graphs of y=t i.e. the identity function.

This is because, in each case, we are taking the composition of a function with its own inverse.


The inverse of a function f is a function that undoes the operation of f. The inverse function is represented by f-1.

So the composition ff-1(t)=t is the mapping of t to t.

y=t is called the identity function because it leaves any input value unchanged.


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plotXpose app is a companion to the book Mathematics for Electrical Engineering and Computing by Mary Attenborough, published by Newnes, 2003.