# Search results

1. ### Can you skip trig substitution?

Like someone said, you never need it until you do. Once you get into DiffEq it will be very useful. Also, if there is a problem in a textbook that needs it, (there will be). Those problems are nearly impossible to do with out it. That being said, it's really not hard at all. Memorize your...
2. ### Calculus I review for Calculus II

If you've got the textbook, I'd just go through and see what concepts you do remember and which you don't.
3. ### Calculus I review for Calculus II

Derivatives and limits, so the two biggies. Also make sure you're well versed in trig. I.E. Trig derivatives and identities. It should be noted that it varies from school to school, L'Hospital's rule for example, I learned that in Cal I at one school, ad then again in Cal II at another school.
4. ### Symbol for partial derivative not used for partial integrals?

I was just trying to think of some example of a differential equation, and that is what I came up with. I'm not sure if we are on the same page. I failed to mention that my calculus background is half way through elementary differential equations, and oversight on my part. When I made the OP...
5. ### Symbol for partial derivative not used for partial integrals?

If you could take ∫xdy=xy+c Withoutt knowing we are working backwards from a partial derivative. Then there would be no need to use seperation of variables when solving a differential equation. For example. xdy-ydx=0 The solution to this is not xy-yx=c Which would be 0=c. The solution is...
6. ### Symbol for partial derivative not used for partial integrals?

This IS a great place. Very intellectually stimulating. I could read threads for hours and hours here.
7. ### Symbol for partial derivative not used for partial integrals?

The first equation was supposed to be with respect to y not x. >.< But regardless, thanks for the info. I'll look into it when I get some time. I should really be doing homework right now too. What has my life become that my idea of procrastination is participating in a math forum??
8. ### Symbol for partial derivative not used for partial integrals?

{\frac{∂(xy)}{∂x}=x} Going backwards. If we took, ∫x dy we get xy+f(x) Now, the only way that ∫x dy is a valid operation, is if we know that we came from a partial derivative. Why, when taking a partial...
9. ### Differential = continuity theorem

Ok, thank you for the clarification. When you're just now learning something, less is more I think. I tend to get bogged down by proofs and theorems when learning new material. It's easier for me to understand the process "numerically" and be able to get an answer, and then go back and see how...
10. ### Differential = continuity theorem

Just to be sure, I don't want to go around tossing out inaccurate advice. My explanation is correct and does suffice for this instance, right? As the instructor just simply wrote down the limit=0 on the board, I just felt like a simple "this is where that came from" answer was all that was needed.
11. ### Differential = continuity theorem

Yep, that should be your goto when trying to solve a limit. And if that doesnt work, well, there are other methods, but you'll get to those if you havent already.
12. ### Differential = continuity theorem

One method we have for solving limits is to simply take the the value that our variable is approaching and plug it in for our variable. In this case we have the limit as x approaches x0 of f(x)-f(x0). So by taking x0 and plugging it in for x, we get f(x0)-f(x0)=0. Therefor the limit(x-->x0)...
13. ### Derivative and Integral notation

Why is it that when you are doing a partial derivative it is expressed something like this. ∂f/∂x=2xy, where f(x,y)=x2y but when doing double or triple integrals you see this ∫∫f(x,y)dxdy. Why is partial notation not used in both?
14. ### Trouble with line integral

If I'm not mistaken ∫2(t^3)+2(sin(2*pi*t))dt=(1/2)(t^4)-(cos(2*pi*t)/pi) you have =2t^4; by simply taking the derivative of this you would get 8t^3, not 2t^3. How does r(t)=ti+2tj not pass through (0,2)? To find the vector of a line segment, it's just <x2-x1...