Question

Never mind it's composite functions..
@jim_thompson5910

Answer 1

(t o s)(x) is the same as t(s(x))

Answer 2

agreed? or do you have a question on that aspect?

Answer 3

so I multiply t by s?

Answer 4

no, t(x) is a function

it does NOT mean t times x

Answer 5

unfortunately this notation is a bit confusing since 3(5) means 3 times 5

but when we refer to functions like t(x), we don't mean t times x

we mean "t is a function where x is the input, t(x) is the output"

Answer 6

okay.. I don't understand how to do them then.

Answer 7

say we had the equation y = x+5

Answer 8

if we plugged in x = 2, we'd get

y = x+5
y = 2+5
y = 7

So the input is x = 2, the output is y = 7

Answer 9

make sense?

Answer 10

yes, so far

Answer 11

ok now let's say we wish to express the equation y = x+5 into function notation

why would we do this? because function notation helps tie together the input AND output in the same equation

instead of saying "input is x = 2, the output is y = 7", which is a bit lengthy, we just write

f(2) = 7

where f(x) = x+5. We just replaced y with f(x). The terms y and f(x) are often interchangeable.