Mint (01-13-2013)
I'm really bored, on holiday right now. Throw me your high school or uni first year problems! Heck, even if you have questions tougher than those, let me try them out too.
I can do up to single variable calculus with confidence... A little shaky on linear algebra, multivar calculus and its theorems but I can try too.
Took AP Biology, AP Chem, AP Physics, AP Stats and AP Calc last year (I'm not from the US so I don't have to take everything).
Generally I can do physics too but am not as good at it as at the other subjects.
Mint (01-13-2013)
I don't understand anything you said. D:
You're on holiday now? You lucky ass. Mine ended yesterday.
(btw, your English is excellent for I assume, Chinese?)
@Joelalala , if you don't understand it, you don't need to...yet,
But for the rec, single var is just solving/involving 1 variable, eg. 'x'.
Multi var is 2 or more, like 'x', 'y', 'z'.
Lin alg usually involves graphs on a Cartesian Plane, and most of the time, can be done by calculator.
Calculus is done by hand (early stages at least), and involves derivation of functions to different orders.
Mine's ending in a couple of weeks. Haha.
Going to have to start studying for the next semester, sucks, but I'm taking a programming module so maybe I can finally do something for clraik
Hey do partial derivatives and optimization in multivar for me
pm me the questions lol i'll like to try them out for fun.
but mind you i suck at multivar in the later stages.
2x(3x-2)+x^2+0.2(x^2+3)
expand + simplify
please explain the steps...i keep getting 2x+1.2x^2+0.6, and that's wrong according to the back of my textbook
Maybe I can help, though I haven't touched algebra in years (and hated it when I did). It might be wrong, but until watersniper comes on to do it himself, this is what I got:
Firstly when you typed "(x^2+3)", I assume you meant "[(x^2)+3]", not "x^5", right?
If so, I got 7.2x^2-4x+0.6, or in fraction form, (36/5)x^2-4x+(3/5)
If I'm right, I can explain. If I'm wrong, you probably wouldn't want me to explain,
@Mod Yes, that's correct. xD
Please explain the steps, and what I'm doing wrong, line by line!
You'll be repped handsomely ~
First, I'll give you what I got when I expanded it, before I explain:
(6x^2)-(4x)+(x^2)+(0.2x^2)+(0.6) , when simplified, is the answer I gave you above. The brackets here are just there to make it easier to see.
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1A. Basic expansion:
-You multiply every term inside the brackets (eg. 3x and -2, that's 2 terms), by every term outside of the bracket (eg. 2x)
-So "2x" * "3x" = "6x^2"
-Remember when you're multiplying here, that you have to do both the number (eg. 2 * 3 = 6), AND the variable (x * x = x^2), hence "6x^2"
-So of the original "2x(3x-2)", we've done the first term. The second term (-2) is a cinch:
-"2x" * "-2" = "-4x"
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1B. Basic expansion (continued):
-And repeat that for the second part of the function "0.2(x^2+3)"
-"0.2" * "x^2" = "0.2x^2"
-"0.2" * "3" = "0.6"
The term in the middle of the expanded form I wrote at the beginning, "x^2" is irrelevant, because it's just there [eg. 2x(3x-2)+x^2+0.2(x^2+3)]. You don't have to do anything to it.
****************************
2. Simplify:
-So you've got the expanded form now, all you do is add/subtract the "like terms". A like term is anything with the same variable type (or just numbers) and power
-(eg. you can do "x^2 + 2x^2 = 3x^2", but cannot do "x + 2x^2", because one is ^2)
-"(6x^2) + (x^2) + (0.2x^2) = 7.2x^2" [or (36/5)x^2, same thing]
-"-4x = -4x" (it's the only term of the same power)
-"0.6 = 0.6" (it's the only term of the same power); 0.6 in fraction is "3/5"
And that leads to 7.2x^2-4x+0.6, or in fraction form, (36/5)x^2-4x+(3/5)
****************************
3. Side-note:
-When writing out simplified answers, always arrange the terms from highest power to lowest
-eg. x^2+x+1, not something whacky like 1+x^2+x
Mint (01-13-2013)