Pink Poogle Toy Forum

wow, thanks m.Bison, your explaination helped me a lot!

No problem. I have an exam coming up Monday on integration techniques (including IBP), so it was good practice for me anyway.

Edit: Heh, while studying for my test this morning, I found out I mixed up the formula for IBP.

It should really be ∫udv = uv - ∫vdu. Though, it didn't make a difference in this case, as e^x is its own antiderivative; I got the right answer using the wrong method (hence why I didn't catch the error sooner). Sorry about that.

Integration... Its hard!
Cant some one help me integrate tan^2 2x?
I Know the integratal of tan^2x = tanx - x + c, but I cannot figure out how to include that 2...

hehe! It doesn't matter, I knew the formula, I just didn't know the process XD How did you do in your test?

Anytime you see composite functions inside an integral (that is, f(g(x))), try looking for ways to apply u-substitution. In this case, g(x) = 2x, and f(g(x)) = (tan(2x))^2.

∫(tan2x)^2 dx

Let u = 2x, du = 2dx.
Solve for dx and you'll find that dx = du/2.
Replace the x's with u's and you'll get:

∫(tanu)^2 du/2

Bring out the constant 1/2 (from the du/2).

1/2 ∫(tanu)^2 du = 1/2(tanu - u).

Replace the u's with what you substituted them for (2x).

1/2(tan2x - 2x). Distribute and add the constant of integration:

(tan2x)/2 - x + C.



It went well. Math is most definitely my strong point, academically.
Unfortunately, the same can't really be said about anything else heh.

Ohh! Thanks M.Bison! I have a bunch of other questions just like these! I'l be able to work them out now ^^;;

I'm doing quadratic graphs here, does anyone know how to find the equation of the line of symmetry of the curve?

Okay, for simplicity here is your quadratic eqn: y = ax^2 + bx + c

Step one is to find the vertex of the equation. Do that by using this equation x = -b/2a.

Once you get this value, plug that value into your original quadratic to get your y value. You now have your vertex.

Now since your equation was in the form y = ax^2 + bx + c, the only point that is really important is that x value, since if you try to graph it, you will notice that the curve will open up or down...

so your answer wouuld be the x = (whatever value you had).

hopefully that helped

I am obviously missing something with this math problem...

(2y+5)-(y+3)+(7y-3y)=17

I came up with 9/5...and I am apparantly wrong. What in the world am I doing wrong?

No problem, Masquerade. Integration can be fun once you get used to it (seriously).



(2y+5)-(y+3)+(7y-3y)=17

First, distribute that negative sign to get (2y+5)-y-3+(7y-3y)=17. Now, because everything else is being added, you can remove the parenthesees.

2y + 5 - y - 3 + 7y - 3y = 17
Combine terms.

(2y - y + 7y - 3y) + (5 - 3) = 17
5y + 2 = 17
Subtract 2 from each side.

5y = 15
Divide each side by 5.

y = 3

By the way, it seems your mistake comes from not properly distributing the negative sign.
I'm guessing you had simplified -(y + 3) to -y + 3? Instead, it should be -y - 3.

-(a + b)
You can think of the - as a "-1":

-(a + b) = -1(a + b)
Therefore, you multiply everything by (or distribute the) -1.

(-1)a + (-1)b = -a - b

Wow, I can't believe I didn't catch that. Thank you so much, you rock. :D

Aha, that sure did. Thanks for the help.

This may sound really dumb, since you guys are all doing algebra, and I am doing financial maths.

I don't know the formula, for weekly costs. I've worked out like say I use something, and it lasts for a whole month what would be my weekly cost.

Like say I buy an item that cost $2.00 eg a packet of chips, and it lasts me for 2 weeks, how much would it cost me weekly? I don't think it is like $2.00 divide 2 = $1.00, since the monthly formula isn't just like dividing by four, to work out the weekly cost. But it could be, I don't really know.

Since if it lasts me monthly it wouldn’t be $0.50. The monthly formula isn’t like amount of cost divide 4 = $0.50. Since you end up with 48 weeks in a year overall. The monthly formula is; the amount the good costs x 12 divide by 52 = answer. Eg; Something costs me $3.00, and it lasts me for a whole month. It would be like; $3.00 x 12 divide 52 = $0.69, and $0.69 is therefore my weekly cost if an item lasts me for one month.

Does anyone know what I mean? Oh also how do you work out days? Like say I buy some chocolate, and it costs me $4.00 and it lasts me three days, how much would it cost me weekly?

Please help me! I will be forever grateful.

First of all, let's assume a week has seven days. Soo... a bag of chips costs two dollars, and it lasts you two weeks.

2 dollars = 2 weeks
divide both sides by 2
1 dollar = 1 week

So yeah, it would be one dollar a week.

Chocolate that lasts you three days?

4 dollars = 3 days
divide both sides by 3
4/3 dollars ($1.33) = 1 day
multiply both sides by 7
28/3 dollars ($9.33) = 1 week

That's pretty much it... just divide both sides by an equal constant.

All right y'all, I really need some help in answering 3 questions over the characters, Damon and Pythias:

--What were their first and last names
--What were some of their contributions
--When were they born and when did they die


All help is very, very much appreciated. I am having a bad day, and I can't find anything that will answer these questions.