Pearson Algebra 2 Common Core, 2011
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Pearson Algebra 2 Common Core, 2011 View details
6. Natural Logarithms
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Exercise 80 Page 483

To algebraically determine the inverse of y, switch x and y and solve for y.

Inverse: y=± sqrt(x-5)
Result: No, The inverse is not a function.

Practice makes perfect
We will begin by finding the inverse of y. We need to switch x and y and solve for y. y=- x^2+5 → x= y^2+5The resulting equation will be the inverse of the given function.
x=y^2+5
x-5=y^2
y^2=x-5
sqrt(y^2)=sqrt(x-5)
y=± sqrt(x-5)
Now that we have found the inverse of y, we will determine whether the inverse is a function. We shall recall that function is a relation where each input is related to exactly one output. In our case, we can see that for each x, there are two values of y. If x=a, then y=± sqrt(a-5). Therefore, the inverse of the function is not a function.