Schoolwork Help Thread

[Zeila]

That sounds sucky :/ hopefully you found other alternatives for learning the material. If you want to know a shortcut for implicit differentiation, then dy/dx = - (Dz/Dx)/(Dz/Dy), where Dz/Dx is the partial derivative of x and y respectively with respect to z = F (x,y) (note that for implicit differentiation, you should have everything equal 0 before you do this, and for partial derivatives, D is actually a greek (?) letter)

In order to calculate partial derivatives, it's actually easier than regular ones. You just treat the other variable as a constant. For example, if you are calculating Fx (Dz/Dx) in the equation z = 2x^2y^3 + 3xy, then you would get 4xy^3 + 3y

Let's say you are trying to find dy/dx in the equation xy - x^2y = 0, you need Fx and Fy (Dz/dy). Fx would equal y - 2xy, and Fy equals x - x^2. Plug that into the equation dy/dx = - Fx/Fy to get dy/dx = - (y - 3xy)/(x - x^2)

Np! And sorry if this is too complicated. It's just simpler than doing implicit differentiation the normal way. I understand if you don't use this because you didn't formally learn/grasp it yet or if it won't be acceptable in tests or something

[Latios212]

Most places I've seen use ∂ (pronounce: "del", write as a backwards 6 lol) for partials, with ∂F/∂x or Fx representing the partial derivative of F with respect to x.

Zeila: My teacher called the above method for calculating derivatives the "god method", because, well, it just works really cool

But of course you don't need to be worrying about this, do you Bubbles? xD What class is this?

[Bubbles]

my brain just did a flip .-. You def sound very smart tho

AP Calc AB. So like beginners calc with a little extra "f you" thrown in

[Dudeman]

Oh hey, I took that two years ago. Are you planning on taking the national exam?

[E. Gadd Industries]

I got really excited when I saw this thread because I'm used to helping people on hw & such, but then I realized that I'm one of the youngest on the forums. :/ Better hit the books!

[Bubbles]

Oh hey, I took that two years ago. Are you planning on taking the national exam?

yes lmao that should be fun

[InsigTurtle]

I suppose this would be the right thread to ask for this?

My math course only goes over synthetic division and long division of polynomials where the divisor is of the form x-a or ax-b. So I was wondering how you'd do it for a divisor of any other type of polynomial. Like, let's say, using dividing x^5-4x^4+2x^3-3x^2-3x+1 by x^3+x+1 as an example.

[Latios212]

Personally I never use synthetic division (because I always forget how to do it, and it's the exact same steps as long division anyway lol).

Long division with polynomials is even more straightforward than with integers - you don't have to worry about borrowing/carrying over since the sum/difference of any x^n term is always an x^n term. Write out the divisor and dividend out, with placeholder zero terms to keep everything aligned nicely. Then look at the first term of each, and divide them (x^5/x^3=x^2 which is the first term of the answer). Then subtract x^2 times the divisor from what's left under the division sign. You get -4x^4+x^3-4x^2-3x. Same thing, divide the first terms. -4x^4/x^2=-4x so that's the next term of the answer. Then subtract -4x times the divisor from what's left under the division sign, yadda yadda yadda. Everything works out nicely here and you get a quotient of x^2-4x+1.

It's pretty similar to integer long division, which is how I can recall it.

[Ruto]

Lol math minor and I haven't seen that ages and I'm too lazy to try. If you could take it now, it's better than taking it later, the high school AP stuff are jokes compared to the college courses.

Anyway, a professor assigned this to her NON-MAJOR chemistry students (CHEM 100) and I'm wondering how they can even do this when I had to look it up myself. I need to ask her to be sure lol, that's how bad it is xD I don't have their book so I've just been using the internet, hope their book actually explains it.



(Name the compound using IUPAC nomenclature)

[BlackDragonSlayer]

I just want to make sure I'm not doing this completely wrong; we've done a few problems similar to this, but none completely identical:

The problem is "Find dy/dx of ∫ sqrt(t) dt, with upper limit being tan x, and lower limit being 0," and my answer is sec^2 (x) sqrt(tan x).

[Altissimo]

Lol math minor and I haven't seen that ages and I'm too lazy to try. If you could take it now, it's better than taking it later, the high school AP stuff are jokes compared to the college courses.

Anyway, a professor assigned this to her NON-MAJOR chemistry students (CHEM 100) and I'm wondering how they can even do this when I had to look it up myself. I need to ask her to be sure lol, that's how bad it is xD I don't have their book so I've just been using the internet, hope their book actually explains it.



(Name the compound using IUPAC nomenclature)

Fuck, why couldn't you have posted this last semester lmao now i want to do it except i dont remember chemistry

i started trying and then gave up

[Oronoco]

That's really not cool for 100-level non-majors. The first and last time I ever had to worry about nomenclature was first semester Organic.

I'm sorry, BDS. Math makes me melt.

[Latios212]

The problem is "Find dy/dx of ∫ sqrt(t) dt, with upper limit being tan x, and lower limit being 0," and my answer is sec^2 (x) sqrt(tan x).

Seems right. Though I will point out the question was phrased incorrectly - it should either say "find d/dx[that]" or "find dy/dx where y=[that]". d/dx is an operator meaning take the derivative, dy/dx is a function that is the derivative of y.

[Ruto]

Eh I would just check with wolfram alpha since I don't have a book or calculator or even paper with me. But is it REALLY asking to take the derivative of an integral? That's an odd thing to ask.

First part eh.



Too lazy to type the second part in but the answer looks right.

The professor never got back to me about the answer to the cyclohexene lol

[Mashi]

I just want to make sure I'm not doing this completely wrong; we've done a few problems similar to this, but none completely identical:

The problem is "Find dy/dx of ∫ sqrt(t) dt, with upper limit being tan x, and lower limit being 0," and my answer is sec^2 (x) sqrt(tan x).

Your answer is correct.  This is the Fundamental Theorem of Calculus joined with Chain Rule is that helps you understand it better.  An easy way to check would be to evaluate yourself by taking the integral and then differentiating.  However, as a word of fair warning, you might see in the future examples where you have to differentiate a function that doesn't have an elementary integral (e^x^2, as a common example), so it'll be useful for you to understand the general process for finding the solution than doing straight evaluations.

Lol math minor and I haven't seen that ages and I'm too lazy to try. If you could take it now, it's better than taking it later, the high school AP stuff are jokes compared to the college courses.

Anyway, a professor assigned this to her NON-MAJOR chemistry students (CHEM 100) and I'm wondering how they can even do this when I had to look it up myself. I need to ask her to be sure lol, that's how bad it is xD I don't have their book so I've just been using the internet, hope their book actually explains it.



(Name the compound using IUPAC nomenclature)

2-Acetyl, 4-Methyl, Cyclohexene-1-ol???  idk, taking a guess lol