Maths Hw
- junglemonkey
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Maths Hw
Ok, just started my higher course. I'm confuddled already. This is a really confusing post, good luck to anyone who can decipher this. Even if you can't, please reply saying something so I know it's been read lol
This is about compositions of functions
I know how to substitute into a function and basically everything up to standard grade. For example:
f(x) = 2x + 1
f(2) = 5
lol i bet I got that wrong.
But now we've moved on to compositions of functions. If you had this would you just substitute in the same way?
f(x) = 2/(x+1) g(x) = (2/x) -1 (I've put in the brackets because in f(x) the denominator is x + 1 but in g(x) the denominator is x)
So to find f(g(x)) and find g(f(x)) would you subsitute in like this? ( a fraction in brackets just indicates the part that is actually in the fraction, it's hard to do this over the internet'
f(g(x)) = f((2/x)-1) (ie. Substitute in the g(x) equation)
f = 2/(2/x)-1 + 1
f = 2/(2/x)
f=x
Please say I am doing this right and you just substitute the other function for x, as if it were any other number or whatever? Damn that was confusing.
Thanks,
Lesley xxx
This is about compositions of functions
I know how to substitute into a function and basically everything up to standard grade. For example:
f(x) = 2x + 1
f(2) = 5
lol i bet I got that wrong.
But now we've moved on to compositions of functions. If you had this would you just substitute in the same way?
f(x) = 2/(x+1) g(x) = (2/x) -1 (I've put in the brackets because in f(x) the denominator is x + 1 but in g(x) the denominator is x)
So to find f(g(x)) and find g(f(x)) would you subsitute in like this? ( a fraction in brackets just indicates the part that is actually in the fraction, it's hard to do this over the internet'
f(g(x)) = f((2/x)-1) (ie. Substitute in the g(x) equation)
f = 2/(2/x)-1 + 1
f = 2/(2/x)
f=x
Please say I am doing this right and you just substitute the other function for x, as if it were any other number or whatever? Damn that was confusing.
Thanks,
Lesley xxx
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- faith
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Re: Maths Hw
wow i left this post feeling 10 times stupider......
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God bless
Love in christ--chelsea
~God created people in his own image; God patterned them after himself Genesis 1:27
~Stop judging others, and u will not be judged. Stop criticizing others, or it will all come back on u. Luke 6:37
~There are "friends" who destroy eachother but a real freind sticks closer than a brother. Proverbs 18:24
~A fool is quick tempered but a wise person stays calm when insulted. Proverbs 12:16
~The tounge is a small thing but what enormous damage it can do. James 3:5
~Even if my father and mother abandon me the Lord will hold me close. Psalm 27:10
~Get rid of all bitterness...instead be kind to eachother Ephesians 4:31-32
God bless
Love in christ--chelsea
- junglemonkey
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Re: Maths Hw
Lol don't, I understand it just as little as you
Anyone??? :'(
Anyone??? :'(
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- noxor
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Re: Maths Hw
yeah, you're doing it right, both answers are x
- junglemonkey
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Re: Maths Hw
Is the last bit definitely right?
2/2x - is it x?
How is that?
I was torn between x and 1/x ... And I don't fully understand how I got that. is it because the 2 divides into the 2 on the numerator, but, it was 2 TIMES 2, so i becomes 1x?
2/2x - is it x?
How is that?
I was torn between x and 1/x ... And I don't fully understand how I got that. is it because the 2 divides into the 2 on the numerator, but, it was 2 TIMES 2, so i becomes 1x?
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- whyaminotaccepted
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Re: Maths Hw
yes
Don't ask me my name: now you know it:
Chichilli Raven Santos
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~It isn't premaritial sex if you have no intention of getting married!!!
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to increase the population,
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Do you get my explantation?
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- diane2ns
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Re: Maths Hw
I got x, and I know IO'm doing it right, I better be, I go to a math academy.
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I used to watch the world pass me by.
I'd sit and wait for it to slow down, but why?
The world gave up on me, that I know.
For the pain goes on, life will no longer glow.
Then one day it hit me like a wall.
There was no reason for me to fall.
For all that I had bottled up inside,
Was a remarkable person waiting to be alive.
- noxor
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Re: Maths Hw
Originally posted by junglemonkey@Jun 15 2003, 01:51 PM
Is the last bit definitely right?
but, it was 2 TIMES 2, so i becomes 1x?
it was 2 * 2?
2/(2/x) means 2 * x / 2 (division is reciprical multiplication)
in other words,
2 * (1/2) * x and not 2 * 2 / x or 2 * (1/2) / x
- junglemonkey
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Re: Maths Hw
Crap. Typo. I meant 2 TIMES X lol.
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- DreamPixie
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Re: Maths Hw
f(x) = 2/(x+1) g(x) = (2/x) -1
f(g(x)) = 2/(((2/x)-1)+1)
= 2/(2/x)
= 1/(1/x) = x
ok, my bad, i got 1/x the first time, but you're right <3
f(g(x)) = 2/(((2/x)-1)+1)
= 2/(2/x)
= 1/(1/x) = x
ok, my bad, i got 1/x the first time, but you're right <3
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- Jaegermeister
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Re: Maths Hw
That's the idea of the equations, you've done them rihgt.
TJ
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Re: Maths Hw
Nice. It looks like everything is right to me.
When you get something like F(G(x)) just think:
What is the answer to G(x) plugged into the F function.
But it looks like you've got that concept already, so good job.
When you get something like F(G(x)) just think:
What is the answer to G(x) plugged into the F function.
But it looks like you've got that concept already, so good job.
"true intelligence is to know the extent of ones ignorance"
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- junglemonkey
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Re: Maths Hw
I under stand now why it is X
If you write this:
f = 2/(2/x) ... And you write it in linear form it becomes clearer because to divide by a fraction you turn it upside down and multiply, therefore the x is not 1/x ...
2/(2/x)
= 2 x (x/2)
= 2x/2 (the twos now cancel)
= x
I've totally got it now
i am VERY thankful to everyone, you guys rock
If you write this:
f = 2/(2/x) ... And you write it in linear form it becomes clearer because to divide by a fraction you turn it upside down and multiply, therefore the x is not 1/x ...
2/(2/x)
= 2 x (x/2)
= 2x/2 (the twos now cancel)
= x
I've totally got it now
i am VERY thankful to everyone, you guys rock
I traded my dreams for this mess of memories
And they just stopped working for me...
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- DownInFlames
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Re: Maths Hw
OMG! I hate algebra with all my heart! When school starts again, I'll have to post one of these with all my problems so you guys can do them for me. I am NOT looking forward to Algebra 2!
Shizzz!
- junglemonkey
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Re: Maths Hw
Originally posted by MyOwnPerson@Jul 11 2003, 06:35 PM
OMG! I hate algebra with all my heart! When school starts again, I'll have to post one of these with all my problems so you guys can do them for me. I am NOT looking forward to Algebra 2!
Lol since I'm not american i have no idea what Algebra 2 is!
I think once you have a good basic understanding of these type of problems, and you can work through them, and check the answers and they're right (sometimes lol) it's extremely satisfying. I went through a long while doing really bad in maths and I mean REALLY bad... And now I'm quite good at it even though we're going on to very hard stuff after summer.
So, MyOwnPerson, hold out and try hard
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