Studying today for my precalc final tomorrow, I've learned nothing in the class all year through having an incompetent grad student for a teacher, so the goal is to teach myself all of precalc today with the help of a friend who's great at math.

I'm having my dad teach me calculus in about 5 minutes :lol:

Pretty sure I've come down with the Flu. my throat feels like smoke is smouldering out each swallow of anything, nose is blocked. eeeergh. Of all the times to get ill.

Pretty sure I've come down with the Flu. my throat feels like smoke is smouldering out each swallow of anything, nose is blocked. eeeergh. Of all the times to get ill.

 

Something's been going around over here too. It's amazing how I didn't get it yet, even though my immune system is crap and I'm around so many sick people.

 

In other news, I got some of my course grades back. Straight A's so far, but I still have a monster of a math test to survive...

Work in an hour. Long night ahead.

Studying today for my precalc final tomorrow, I've learned nothing in the class all year through having an incompetent grad student for a teacher, so the goal is to teach myself all of precalc today with the help of a friend who's great at math.

http://www.khanacade...rg/#precalculus

 

You know, looking at that I feel even more incompetent in the subject and less prepared for calculus. We never learned limits, permutations, binomail theorem, parametric equations, shit I dont recognize half the things on that list. But thanks for that, I'll be using it.

How the hell do you learn Calculus and not limits?

 

Limits are the thing they force you to learn before they let you derive or integrate, because you need to know how that stuff actually works before they give you the formulas that make everything so much easier. I may have jetesoned my knowledge of how to work with limits at the first sign I wouldn't ever have to do them by hand again in my life, but there are some fundamental concepts in there that are fairly important if you ask me. Without ever having gone through that, calculus is just a bunch of magical formulas. You might as well be performing mathematical witchcraft :P

 

Also, don't fall asleep to Criminal Minds. It turns your mind into a kaleidoscope of crazy. I did get to drive a Ferrari (only in my head) though, which I guess is a bonus?

 

Not a whole lot else going on. I learned that if I don't put shoes and socks on that my room is apparently cold enough to make my feet go numb, but not cold enough to make me go put my shoes on until I want to go someplace. Also, its raining, though I cant say that's new. It seems to be slowly becoming the new norm here weather wise, though maybe that means we'll end up with a lot of snow before Christmas (I do love a white Christmas. The last few have been a little on the green side).

I'm in precalculus, not calculus. I also have no idea what derive or integrate means, should I at this point? Probably.

Pre-Calc doesn't deal with integration or derivation. Those are the core of real Calculus. Pre-Calc should eventually deal with permutations towards the end of the grade 12 level, and the last thing you do will probably be a bit of work with limits. If your in grade 10 or 11, then that's why you don't have any idea what I am talking about.

I'm in my first semester of college.

Well, if you haven't studied it yet, I guess you don't need to know it.

 

This is making me realise that while I might remember the concepts of Calculus, I probably couldn't manage to derive y=x^2 (I know its y=x, just not how to get it) without needing to look something up. My how the math skills atrophy when they aren't used anymore. Freaky. This almost makes me want to read my calculus for dummies book tonight and brush up, because I can objectively observe myself getting dumber (math wise).

 

Someone bear with me while I do some calculus to make myself feel better (there's a phrase you aren't going to hear much):

 

y=2x^2

 

y'=(2)2x^(2-1)

=4x^1

=4x

 

There, I can still do the power rule. Yay me.

The derivative of y=x^2 is y'=2*x :P (and derive does not mean differentiate)

EDIT: you changed it to 2*x^2, and yes, did it correct :grin:

 

 

Anyway, I was also hoping that I would never have to do limits again, but apparently they need to be re-introduced when you start doing complex analysis and differentiation in the complex plane. It's also much more difficult :(

BUT the calculus exam I just finished marks the last "pure math" course I will take for my degree. That being said, all of my classes are based on math so nothing has really changed.

The derivative of y=x^2 is y'=2*x :P (and derive does not mean differentiate)

 

 

Anyway, I was also hoping that I would never have to do limits again, but apparently they need to be re-introduced when you start doing complex analysis and differentiation in the complex plane. It's also much more difficult :(

BUT the calculus exam I just finished marks the last "pure math" course I will take for my degree. That being said, all of my classes are based on math so nothing has really changed.

:wall:

 

And that's what happens when you don't touch calculus for almost a full year.

 

Doesn't matter now. I'm either going to finish my degree in Economics, which is mostly statistics, or I'll get into paramedicine. If I stay in Eco, I'll have to take some calculus, but probably nothing even close to the stuff I was doing in Engineering.

Someone bear with me while I do some calculus to make myself feel better (there's a phrase you aren't going to hear much):

 

y=2x^2

 

y'=(2)2x^(2-1)

=4x^1

=4x

 

There, I can still do the power rule. Yay me.

Now try product rule. :P

Doesn't matter now. I'm either going to finish my degree in Economics, which is mostly statistics, or I'll get into paramedicine. If I stay in Eco, I'll have to take some calculus, but probably nothing even close to the stuff I was doing in Engineering.

Ah cool, statistics was never my strong point in math.

Engineering ftw :shades:

 

Product rule for that same function:

0 + [copy and paste his solution]

Oh lets see, this takes me back. My only beef here is that these rules are normally used trig functions. Oh well, I have a chart knocking around for that.

 

Product Rule: d/dx (uv) = u'v +uv'

 

so for y = 5x^(2)sin(x)

let u = 5x^2 and u' = 10x

let v = sin(x) and v' = cos(x)

 

y'=10x sin(x) + 5x cos(x)

 

Quotient Rule: d/dx (u/v) = (u'v - uv')/v^2

 

so for y = [sin(x)]/[2x^3]

let u = sin(x) so u' = cos(x)

let v = 2x^3 so v' = 6x^2

 

y'= [2(x^3)cos(x) - 6(x^2)sin(x)]/4x^6

= 2(x^2)[(x)cos(x) - 3sin(x)]/4x^6

= [(x)cos(x) - 3sin(x)]/2x^4

 

Think I did all that right. And no, I am not going to do the chain rule right now.

I had an off day today, I kept interpreting things in a different language (if you cant guess it, well, too bad :P ) today versus English, which is really odd for me

Fun way to remember the quotient rule:

 

low dee high minus high dee low all over low low.

 

low=denominator

dee=derivative of

high=numerator

[bleep] you guys, I just spent 4 hours doing calculus and I get back to see you doing derivatives. Luckily derivatives are easy. I need to figure out how to do implicit differentiation though.

Optics test today. I honestly have no idea how I did, hopefully decent. I'm hoping to pull my science mark up - I'm sitting low 80s or high 70s; I was hoping to be in the 90s.

[bleep] you guys, I just spent 4 hours doing calculus and I get back to see you doing derivatives. Luckily derivatives are easy. I need to figure out how to do implicit differentiation though.

 

 

xy^2+y+yx^3 = 3

 

[(y^2)+(2xyy')]+y'+[(y'x^3)+(3yx^2)] = 0

 

Just collect all of the y' s to one side.

 

 

 

And if you need some help, just pm me or something.

Why can everyone here do Calculus. This is creepy. I'm not used to being around a bunch of mathy people anymore :ohnoes:

 

Still raining, which is nice. I love the sound of rain on the roof when I am going to sleep. I remember one of the beaches I used to lifeguard at sometimes used a shipping container as a storage unit for the gear (actually, a number of our beaches are like that), and it acts as shelter when its raining and there is no one at the beach. My partner liked to go to sleep on the heavy rain days (I think the best was when his mother showed up and found him sleeping). Anywho, the rain was really loud inside the container (being all metal and all), and I found it to be an awesome sound.

Statistics is way cooler than calculus. And more useful.

 

Today I got called in to valet, so I made $11/hr on pay roll, and $20 on tips. Was a nice night considering I was just planning on 'studying' during that time frame anyway.

(1 - x^2)y'' - 2xy' + n*( n + 1)y = 0

 

Solve that differential equation. :3

 

Just felt the need to share some of what I've been doing.

Don't make me post my intellectual history prompts. They make calculus seem like a breeze ;-)