The Calculus Help Thread

**dgsblb2** · 03-08-2009 05:25 PM

Simple (unlike calculus).

Post up whatever questions you have and others will try and help.

**dgsblb2** · 03-08-2009 05:26 PM

First up, can anyone give me confidence that these are right? I'm pretty sure, but a second opinion wouldn't hurt. They are kind of oddball questions.

**jordanj2133** · 03-08-2009 05:53 PM

I just got an engineering degree and that brought back terrible memories. Good luck. And sorry, I don't remember my calc too well.

**Clemson_Fan** · 03-08-2009 07:36 PM

the first one looks right. It looks like you use shell method I did it using another method.

the second however is wrong. You cant offset the sqrt with the ^2.
remember that the area of a circle is pi*r^2. By doing the integral your finding the area of infinitely many circles from lowerbounds to upperbounds. so in the equation the radius of your circle is R=sqrt(r^2-x^2). also notice that the integral is in the form dx this means that the radius is the same as y=sqrt(r^2-x^2). with x bounds being from 0 to r. This is a quarter circle in quadrant one which makes the volume of a hemisphere.

Edit:
To prove this do the integral it comes out to be (2/3)r^3*pi. volume of a sphere is (4/3)*r^3*pi notice its half the volume of a sphere.

**NJ Joe** · 03-09-2009 07:28 AM

There is a creepy link between longboarding and engineering. I don't like it. >: (

**Shimotakimas** · 03-12-2009 12:25 PM

I can promise you I'll use this thread in the near future. I'm reconsidering my major, I hate chemistry too much and Im not a big fan of calculus either. Would you engineers say it gets easier? Or does it get harder and harder as the years go by?

**NJ Joe** · 03-12-2009 12:31 PM

Originally Posted by Shimotakimas

I can promise you I'll use this thread in the near future. I'm reconsidering my major, I hate chemistry too much and Im not a big fan of calculus either. Would you engineers say it gets easier? Or does it get harder and harder as the years go by?

You need high level calc for chemistry? IIRC, chem majors at rutgers only need one year of calc

**Clemson_Fan** · 03-12-2009 01:04 PM

Originally Posted by NJ Joe

You need high level calc for chemistry? IIRC, chem majors at rutgers only need one year of calc

Chem E maybe

Im in second semester Junior year, around sophomore year you stop learning new math and start learning applications. For example in rand signal analysis we learn how to use calculus which we already know and apply that to random signals (Finding probability and such). The only thing I have actually learned as a junior is convolution everything else is just further refinement.

**dgsblb2** · 05-26-2009 03:10 PM

Ok, I give up. I haven't looked at this in a while and it's on the final. + rep for whoever can help.

integrate xe^-x from 0 to infinity

It's an improper integral.

**indiana_boarder** · 05-28-2009 07:50 AM

Originally Posted by NJ Joe

There is a creepy link between longboarding and engineering. I don't like it. >:#(

Completely true man. Over 90% of the longboarders at my school are engineers. One of them being me. =]

**tomahawk** · 05-28-2009 01:30 PM

Originally Posted by NJ Joe

You need high level calc for chemistry? IIRC, chem majors at rutgers only need one year of calc

depends where you wanna roll with it. if you're just doing basic chemistry/biochem stuff, you prolly will never touch calc ever. if you decide to go into quantum chemistry stuff, or more materials sciency chem, you bet your ass you'll need an advanced level of calc

as for cheme, calc will become your bestest friend, whether you like it or not. for fluid mechanics, differntial equations will bend you over and make your their bitch, for kinetics, solving complex systems of equations will be the main fun, for process control, laplace/fourier transforms will dominate you, for stat mech/thermo, statistics and/or lots of diff eq will be the main fun.