Home | Community | Message Board


Vaposhop
Please support our sponsors.

Community >> The Pub

Welcome to the Shroomery Message Board! You are experiencing a small sample of what the site has to offer. Please login or register to post messages and view our exclusive members-only content. You'll gain access to additional forums, file attachments, board customizations, encrypted private messages, and much more!

Jump to first unread post. Pages: 1 | 2 | Next >  [ show all ]
OfflineBlake_Shroom
Stranger
 User Gallery

Registered: 09/09/09
Posts: 1,036
Last seen: 8 months, 8 days
Brain fart! Need math help! Nerds come please :)
    #11303665 - 10/23/09 01:27 AM (7 years, 11 months ago)

So in calculus we have to find the derivative. I know how to do that, but i completely forgot how to work with sin/cos/tan, ect.

How can i make Cos(3x)2 (the 2 is squaring the 3x, I dont know how to make a little 2 lol)

So how can i make something like that, end up like 2cos3x?(thats just an example)

I need to figure out what the 3x does to the equation and same with the square. I think the squre can be changed to the front of the equation like 2cos(3x) but i'm not really sure.

THanks for the help!


Post Extras: Print Post  Remind Me! Notify Moderator
Offlinedkamp18
The Real World


Registered: 07/06/07
Posts: 894
Last seen: 7 years, 3 months
Re: Brain fart! Need math help! Nerds come please :) [Re: Blake_Shroom]
    #11303813 - 10/23/09 02:01 AM (7 years, 11 months ago)

sin,cos,tan^-1

if i understood your question right. not sure i did, lol, sorry.


Post Extras: Print Post  Remind Me! Notify Moderator
Invisiblepwnasaurus
Stranger
I'm a teapot User Gallery

Registered: 07/16/08
Posts: 12,317
Loc: Canada Flag
Re: Brain fart! Need math help! Nerds come please :) [Re: Blake_Shroom]
    #11303820 - 10/23/09 02:04 AM (7 years, 11 months ago)

Quote:

Blake_Shroom said:
So in calculus we have to find the derivative. I know how to do that, but i completely forgot how to work with sin/cos/tan, ect.

How can i make Cos(3x)2 (the 2 is squaring the 3x, I dont know how to make a little 2 lol)

So how can i make something like that, end up like 2cos3x?(thats just an example)

I need to figure out what the 3x does to the equation and same with the square. I think the squre can be changed to the front of the equation like 2cos(3x) but i'm not really sure.

THanks for the help!




dy/dx of y = cos(3x)^2  (the '^' means to the power of) is:

2cos(3x)*-sin(3x)*3
= -6cos(3x)*sin(3x)

This is due to the chain rule.  If you need a further explanation let me know.


Post Extras: Print Post  Remind Me! Notify Moderator
OfflineNeuron
Tek Savant
Male


Registered: 12/28/08
Posts: 5,778
Loc: @meriKa
Last seen: 7 years, 1 month
Re: Brain fart! Need math help! Nerds come please :) [Re: pwnasaurus]
    #11303828 - 10/23/09 02:08 AM (7 years, 11 months ago)

pwnasaurus is so sexy with his red lipstix and math equations :wink:


--------------------


Post Extras: Print Post  Remind Me! Notify Moderator
Invisiblepwnasaurus
Stranger
I'm a teapot User Gallery

Registered: 07/16/08
Posts: 12,317
Loc: Canada Flag
Re: Brain fart! Need math help! Nerds come please :) [Re: Neuron]
    #11303847 - 10/23/09 02:14 AM (7 years, 11 months ago)

No lipstick Neuron - my lips are just naturally sexy as fuck :wink:


Post Extras: Print Post  Remind Me! Notify Moderator
OfflineBlake_Shroom
Stranger
 User Gallery

Registered: 09/09/09
Posts: 1,036
Last seen: 8 months, 8 days
Re: Brain fart! Need math help! Nerds come please :) [Re: pwnasaurus]
    #11303880 - 10/23/09 02:24 AM (7 years, 11 months ago)

Ahhh thanks man. like i said i had a brain fart and forgot lol. Thanks


and since you are so good at this, and so nice :smile:, wanna help me with another?

Evaluate the derivative  of y=4sinx-x @ x=(pi) (dont have to pi symbol on my keyboard lol)


thanks a ton man!


Post Extras: Print Post  Remind Me! Notify Moderator
Invisiblepwnasaurus
Stranger
I'm a teapot User Gallery

Registered: 07/16/08
Posts: 12,317
Loc: Canada Flag
Re: Brain fart! Need math help! Nerds come please :) [Re: Blake_Shroom]
    #11303913 - 10/23/09 02:34 AM (7 years, 11 months ago)

dy/dx = 4cos(x) - 1
dy/dx @ pi = 4cos(pi) - 1
          = 4(-1) - 1
          = -5


Post Extras: Print Post  Remind Me! Notify Moderator
OfflineNeuron
Tek Savant
Male


Registered: 12/28/08
Posts: 5,778
Loc: @meriKa
Last seen: 7 years, 1 month
Re: Brain fart! Need math help! Nerds come please :) [Re: pwnasaurus]
    #11303925 - 10/23/09 02:37 AM (7 years, 11 months ago)

I wonder who is better at math, pwnasaurus or Coaster?


--------------------


Post Extras: Print Post  Remind Me! Notify Moderator
OfflineBlake_Shroom
Stranger
 User Gallery

Registered: 09/09/09
Posts: 1,036
Last seen: 8 months, 8 days
Re: Brain fart! Need math help! Nerds come please :) [Re: Neuron]
    #11303954 - 10/23/09 02:43 AM (7 years, 11 months ago)

you're a life saver man.

How about this one? Determine the points at which y=X^4-2x^2+2 has a horizontal line.

Or Find the derivative of y=cos^2*3x  (I dont know what to do when just the cosine is squared)

Or find the derivative y=cos(3x)^2 (all these problems are the same setup, just a few things that tweek the outcome. Like i said, i forgot all of these rules. maybe a lil too much booze lol)

Thank you sooooo much for all of the help! I got a huge test tomorrow


Post Extras: Print Post  Remind Me! Notify Moderator
InvisibleDieCommie

Registered: 12/11/03
Posts: 29,008
Re: Brain fart! Need math help! Nerds come please :) [Re: Neuron]
    #11303981 - 10/23/09 02:51 AM (7 years, 11 months ago)

Quote:

Neuron said:
I wonder who is better at math, pwnasaurus or Coaster?




Easy question!


Post Extras: Print Post  Remind Me! Notify Moderator
OfflineNeuron
Tek Savant
Male


Registered: 12/28/08
Posts: 5,778
Loc: @meriKa
Last seen: 7 years, 1 month
Re: Brain fart! Need math help! Nerds come please :) [Re: DieCommie]
    #11303993 - 10/23/09 02:55 AM (7 years, 11 months ago)

Quote:

DieCommie said:
Quote:

Neuron said:
I wonder who is better at math, pwnasaurus or Coaster?




Easy question!




lol, I love it.

Even though Coast has a bachelors in mathematics, methinks he does 2 many drugs to retain all the mathematical rules/theorems.


--------------------


Post Extras: Print Post  Remind Me! Notify Moderator
InvisibleDieCommie

Registered: 12/11/03
Posts: 29,008
Re: Brain fart! Need math help! Nerds come please :) [Re: Neuron]
    #11303995 - 10/23/09 02:56 AM (7 years, 11 months ago)

Yea, Ive seen plenty of people get degrees and still not know shit in their subject.


Post Extras: Print Post  Remind Me! Notify Moderator
Invisiblepwnasaurus
Stranger
I'm a teapot User Gallery

Registered: 07/16/08
Posts: 12,317
Loc: Canada Flag
Re: Brain fart! Need math help! Nerds come please :) [Re: Blake_Shroom]
    #11304005 - 10/23/09 03:00 AM (7 years, 11 months ago)

Quote:

Blake_Shroom said:
you're a life saver man.

How about this one? Determine the points at which y=X^4-2x^2+2 has a horizontal line.

Or Find the derivative of y=cos^2*3x  (I dont know what to do when just the cosine is squared)

Or find the derivative y=cos(3x)^2 (all these problems are the same setup, just a few things that tweek the outcome. Like i said, i forgot all of these rules. maybe a lil too much booze lol)

Thank you sooooo much for all of the help! I got a huge test tomorrow




y = x^4-2x^2+2

dy/dx = 4x^3 - 2*2x

Horizontal line would be when dy/dx = 0 so:

0 = 4x^3 - 4x
  = x^3 - x
  = x(x^2 - 1)
  = x(x-1)(x+1)
x = 0, 1, -1

For all three of those values the derivative is a horizontal line.

The second one doesn't make sense.  You can't "just square cos".

However, there is a convention, where if you write

cos^2(x) = (cos(x))^2.  So chain rule once again.


Post Extras: Print Post  Remind Me! Notify Moderator
Invisiblepwnasaurus
Stranger
I'm a teapot User Gallery

Registered: 07/16/08
Posts: 12,317
Loc: Canada Flag
Re: Brain fart! Need math help! Nerds come please :) [Re: pwnasaurus]
    #11304013 - 10/23/09 03:02 AM (7 years, 11 months ago)

I'm going to bed now though, as I have TWO tests tomorrow and an assignment to do.  Good luck buddy.  Night shroomery :mushroom2:


Post Extras: Print Post  Remind Me! Notify Moderator
Offlinestarfirex
Cactus Hippy
Male User Gallery


Registered: 09/04/09
Posts: 635
Loc: New Mexico
Last seen: 2 years, 4 months
Re: Brain fart! Need math help! Nerds come please :) [Re: Blake_Shroom]
    #11304502 - 10/23/09 07:51 AM (7 years, 11 months ago)

expand the cos(3x^2)with the identity cos(u)=[{e^iu)+e^(-iu)}]/2 where i is the operator square root of negative one and e is the base of the natural logarithm.  I believe this is a variant of euler's identity but I'm an engineer and we do all this on computer now rather than fuck with formulas.


--------------------
If the neighbors complain 'cause the music is too loud, turn it up so you can't hear them bitch. ~ I'm blowing my mind....one ass-kicking trip at a time.... :cool:


Post Extras: Print Post  Remind Me! Notify Moderator
Invisiblepwnasaurus
Stranger
I'm a teapot User Gallery

Registered: 07/16/08
Posts: 12,317
Loc: Canada Flag
Re: Brain fart! Need math help! Nerds come please :) [Re: starfirex]
    #11304539 - 10/23/09 08:12 AM (7 years, 11 months ago)

Quote:

starfirex said:
expand the cos(3x^2)with the identity cos(u)=[{e^iu)+e^(-iu)}]/2 where i is the operator square root of negative one and e is the base of the natural logarithm.  I believe this is a variant of euler's identity but I'm an engineer and we do all this on computer now rather than fuck with formulas.




This is complex analysis, and is not related to his calc 1 course.  Definitely don't do this.


Post Extras: Print Post  Remind Me! Notify Moderator
Offlinestarfirex
Cactus Hippy
Male User Gallery


Registered: 09/04/09
Posts: 635
Loc: New Mexico
Last seen: 2 years, 4 months
Re: Brain fart! Need math help! Nerds come please :) [Re: pwnasaurus]
    #11304551 - 10/23/09 08:19 AM (7 years, 11 months ago)

This is too in calc one, if I remember correctly.  You learn the identities for log and ln derivitaves in calc 1.  But yes, you will also get it again and have to do the proofs in complex variable course.


--------------------
If the neighbors complain 'cause the music is too loud, turn it up so you can't hear them bitch. ~ I'm blowing my mind....one ass-kicking trip at a time.... :cool:


Post Extras: Print Post  Remind Me! Notify Moderator
InvisibleDieCommie

Registered: 12/11/03
Posts: 29,008
Re: Brain fart! Need math help! Nerds come please :) [Re: pwnasaurus]
    #11305144 - 10/23/09 11:34 AM (7 years, 11 months ago)

Quote:

pwnasaurus said:
Quote:

starfirex said:
expand the cos(3x^2)with the identity cos(u)=[{e^iu)+e^(-iu)}]/2 where i is the operator square root of negative one and e is the base of the natural logarithm.  I believe this is a variant of euler's identity but I'm an engineer and we do all this on computer now rather than fuck with formulas.




This is complex analysis, and is not related to his calc 1 course.  Definitely don't do this.




Seriously, why the fuck would anybody do that.  No engineer would take a simple derivative by doing that.


Post Extras: Print Post  Remind Me! Notify Moderator
Offlinestarfirex
Cactus Hippy
Male User Gallery


Registered: 09/04/09
Posts: 635
Loc: New Mexico
Last seen: 2 years, 4 months
Re: Brain fart! Need math help! Nerds come please :) [Re: DieCommie]
    #11305251 - 10/23/09 12:09 PM (7 years, 11 months ago)

No engineer takes a derivative of anything.  That's why I said we use  computers.


--------------------
If the neighbors complain 'cause the music is too loud, turn it up so you can't hear them bitch. ~ I'm blowing my mind....one ass-kicking trip at a time.... :cool:


Post Extras: Print Post  Remind Me! Notify Moderator
InvisibleDieCommie

Registered: 12/11/03
Posts: 29,008
Re: Brain fart! Need math help! Nerds come please :) [Re: starfirex]
    #11305277 - 10/23/09 12:16 PM (7 years, 11 months ago)

:rolleyes:  What exactly do you engineer?  An engineer who cant take the derivative of a simple sine function isnt much of an engineer IMO.


Post Extras: Print Post  Remind Me! Notify Moderator
Jump to top. Pages: 1 | 2 | Next >  [ show all ]

Community >> The Pub

Similar ThreadsPosterViewsRepliesLast post
* Funny picture for math nerds.
( 1 2 3 all )
OneMoreRobot3021 3,295 46 10/07/08 09:28 PM
by isaacein
* Fuck, I just had a brain fart and missed my math final.
( 1 2 all )
Konnrade 1,333 22 12/15/05 03:47 AM
by Konnrade
* Math nerds unite!
( 1 2 all )
SubGen1us 1,434 36 11/03/08 05:13 PM
by Cepheus
* College leval math tutorials
( 1 2 all )
blewmeanie 1,988 23 10/13/08 06:16 PM
by deCypher
* New math! Tedwilto 573 15 12/23/08 04:22 PM
by k4ge
* Fun with maths! Krishna 595 5 04/25/04 12:11 PM
by phi1618
* having a brain fart here(maths)... DistortedEyes 585 9 11/07/06 04:43 PM
by sleepy
* Brain Fart Terrapin77 561 4 06/29/06 05:57 AM
by Terrapin77

Extra information
You cannot start new topics / You cannot reply to topics
HTML is disabled / BBCode is enabled
Moderator: Entire Staff
1,011 topic views. 10 members, 85 guests and 27 web crawlers are browsing this forum.
[ Toggle Favorite | Print Topic | Stats ]
Search this thread:
SoulSpeciosa Kratom
Please support our sponsors.

Copyright 1997-2017 Mind Media. Some rights reserved.

Generated in 0.044 seconds spending 0.005 seconds on 21 queries.