4-5

This week was weird. I really don't remember too much of what went on in school. Friday, we took a test and the other days were review, I believe. One of the sections on the test was section 4-5. Section 4-5 was about finding inverses.

To find an inverse you have to use the horizontal line test. This is like the vertical line test, but it's horizontal. If it passes without touching two points on the graph then there is an inverse that is a function.

This brings us to the first step - drawing the graph. Since I don't have a fancy laptop, I can't draw a graph. But, here are some hints to see if it will pass the test. If it has an x^2, it will not pass the test because x^2 makes a parabola. An x makes a straight kinda slanted line.

After you graph, to find an inverse switch x and y. Then solve for y.


For example, y = x + 3

First, graph the equation.

By using the horizontal line test, you know that there is an inverse.

Now, switch the x and y.

x = y + 3

And now, solve for y.

y^-1 = x - 3

Place -1 above y to show that it is the inverse.