Function Notation

This week I am going to explain how to work function notation problems. Which is very easy. All your really doing is basic algebra, which you should already know. So before I work some examples, you are going to need a few notes.

NOTES:

• (f+g)(x) means to add the f(x) equation and the g(x) equation.
• (f-g)(x) means to subtract the f(x) equation and the g(x) equation.
• (fxg)(x) means to multiple the two equations together.
• (f/g)(x) means to divide the two equations.
• (fºg)(x) or f(g(x)) means to replace all the x's in f(x) with g(x)
• If x is replaced with a number, plug into the equation.

Okay, so you are going to use those formulas to work the problems I am about to show you. SO here are some easy examples:

EXAMPLE 1: Using this equation f(x)=2x+1 and g(x)=x-4 find: (f+g)(2)

• You are going to replace all the x's with 2.
• 2(2)+1 + 2-4
• Once you do that, all you have to do is just solve the problem.
• So your answer is going to be 3.

EXAMPLE 2: Using this equation f(x)=x^2+x and g(x)=x+1 find: (f+g)(x)

• Since they don't give you any number to replace the x's for you are just going to work the problem as far as you can. But DO NOT solve for x. That isn't going to be your answer.
• x^2+x + x+1
• Once you have that as your problem you are going to factor.
• Once you factor you are going to get (x+1)(x+1) which is going to be your answer.

And that is how you work function notation problems! WOOHOO.

--Halie