## Function Notation: If f(x) = 2x+1, g(x) = 3-x, find f(a),

Complex numbers, rational functions, logarithms, sequences and series, matrix operations, etc.
Martingale
Posts: 333
Joined: Mon Mar 30, 2009 1:30 pm
Location: USA
Contact:

### Re: Function Notation: If f(x) = 2x+1, g(x) = 3-x, find f(a),

Does this make more sense:
2f(x)=2(2x+1)=4x+2
this is correct

stapel_eliz
Posts: 1628
Joined: Mon Dec 08, 2008 4:22 pm
Contact:
If ƒ(x) = 2x + 1, Find 2ƒ(x)
I originally worked it out like this:
ƒ(2(x))= 2(2(x)+ 1)
But 2 * f(x) is not at all the same thing as f(2*x). This is, in part, a result of the fact that the parentheses, in function notation, have nothing to do with multiplication.
Does this make more sense:
2f(x)=2(2x+1)=4x+2
Yes; two times f(x) means 2(f(x)) = 2(the formula for f) = 2(2x + 1).

Good job!

jolie3000
Posts: 10
Joined: Sat Apr 18, 2009 10:13 pm
Contact:

### Re: Function Notation: If f(x) = 2x+1, g(x) = 3-x, find f(a),

YYYYYYYAAAAAAAA! thank you so very much for your help you guys. I am forever grateful