# Functions Help

Watch
Announcements
#1
Can anyone help me with functions? I don't get them at all. I would really appreciate it. Thank you.
0
3 years ago
#2
(Original post by SyncIn)
Can anyone help me with functions? I don't get them at all. I would really appreciate it. Thank you.
What exactly is the issue?
0
#3
(Original post by RDKGames)
What exactly is the issue?
I just don't get them. Not even fg(x). Can you explain please?
0
3 years ago
#4
fg(x) are functions, meaning, you can put any number of x into it, and it will spit out a number. When you have something like fg(x), its essentially a function inside a function. But don't think too much on that, because when it gets to fghhfgh(x), youll get confused.

Let's say
f(x) = 2x + x^2
g(x) = x+3
Now fg(x) means you're putting g into f, if it was fgh(x), you're putting h into g, then all that into f. Always right to left (just for convention, no real reason). Now algebraically, to solve this, you put g into f. How?

You're gonna take all of g, and wherever you see x, you're gonna replace it with all of g. So

fg(x) = 2(x+3) + (x+3)^2. All you've done is, replace x with whatever g(x) equalled. Brackets are important. Usually clean it up, to get the final marks.
0
3 years ago
#5
(Original post by SyncIn)
I just don't get them. Not even fg(x). Can you explain please?
is shorthand notation for which means you take your function and substitute it into by replacing every with whatever is. What's confusing about this?
0
#6
(Original post by RDKGames)
is shorthand notation for which means you take your function and substitute it into by replacing every with whatever is. What's confusing about this?
Can you give an example?
0
3 years ago
#7
(Original post by SyncIn)
Can you give an example?
One was given in post #4 but here's one:

0
#8
Can you give me a simple question. I will try it.
0
3 years ago
#9
(Original post by SyncIn)
Can you give me a simple question. I will try it.
Given that and determine the expressions for and hence find the values of and
0
#10
(Original post by RDKGames)
Given that and determine the expressions for and hence find the values of and
Never mind, I'll just go on youtube.
0
#11
And sorry for the hassle
0
X

new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### Poll

Join the discussion

#### If you don't put your camera on in online lessons, why is that?

My teacher doesn't want us to (45)
17.51%
No one else does (81)
31.52%
I'm embarrassed about my background (28)
10.89%
I feel self-conscious showing my face (87)
33.85%
We don't use a video platform (4)
1.56%
I don't have a camera (6)
2.33%
Something else (tell us in the thread) (6)
2.33%