To find the inverse of the function y = x² + 4x + 4, we first replace y with x and x with y:
x = y² + 4y + 4
Next, we rearrange the equation to isolate y on one side of the equation:
x - 4 = y² + 4y
y² + 4y = x - 4
Now, we complete the square by adding (4/2)² = 4 to both sides of the equation:
y² + 4y + 4 = x
We can rewrite the left side of the equation as (y + 2)²:
(y + 2)² = x
Finally, we take the square root of both sides of the equation and solve for y:
y + 2 = ±√x
y = ±√x - 2
Since the original function is not one-to-one, we need to restrict the domain to obtain the inverse function. Specifically, we restrict the domain of the original function to x ≥ -2, since for values of x less than -2 there are two corresponding y-values. Therefore, the inverse function of y = x² + 4x + 4 for this restricted domain is:
y = ±√x - 2, x ≥ -2