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Can you help me with basic math? *I'm embarrased*?
Before you judge me, I was in a car accident and got badly injured the start of the year so I had to take time of from school and focus on my recovery. Then summer vacation came and it's over now. My teacher didn't go hard on me in the beginning, so he's helping with composition function and we're starting from the basic...
Anyways, enough of my life story there are 2 questions I couldn't bring myself to ask him because I was too embarrased lol.. I've learned it before, but I forgot it.
= –(2 x + 3) 2 + 5
= –(4 x 2 + 12 x + 9) + 5
where did the 12x come from?
second is function composition:
it says f(x)= x+2/x-1 and g(x)=2/x
fog= f(g(x)) = 2/x +2 / 2/x -1 = 2/x + 2x/x / 2/x - x/x = 2x + 2 / x / 2-x /x ... (I understand the rest)
can anyone.. please... explain... what.the.****. is going on?
1 Answer
- 8 years agoFavorite Answer
The 12x came from when you squared the (2x+3).
When you take the composite of a function, you put one function in place of x in another function, and then solve.
So, since f(x) is (x+2)/(x-) and g(x) is 2/x, then in f(g(x)), wherever there is an x in f(x)'s function, you would put the function for g(x), and then simplify.