tupla_s
.
+455|7027|Finland

sneakysegan11 wrote:

how do you put a degrees symbol?
alt + (numpad) 248 = °

Last edited by tupla_s (2006-12-13 11:45:58)

Chuckles
Member
+32|6983
Wait a minute, you beat some kid up, got suspended, and your teacher is the asshole because he/she sent you some incredibly easy quiz to work on?  Way to beat up a "little freshman", stud. 

First of all, the teacher should have just given you an F for everything you missed.  Secondly, can't you take it upon yourself to actually crack open the book, read the chapter, and learn how to do it yourself? 

You guys that just handed him the answers are just as bad.  This kid clearly isn't too sharp, and needs to do all the learning he can.  I can see walking him through it, but make him do some of it.  I wasn't very good at math either, but I worked at it. 

Sneaky, I'm going to give you a couple of pieces of advice.  First, quit beating people up.  It will serve you absolutely no good in life to have that in your past.  On the oater hand, learning your own math will actually have a positive affect on your life prospects.
mtb0minime
minimember
+2,418|7089

Even though I gave him the answers, I agree with you. I'm just building him up so that when the test rolls around and he has no idea what to do because he was cheating on the homework, he'll fail and hopefully learn a lesson.

Plus I'm a super math nerd and couldn't help it anyway. And for you people contesting my answer for 1b, please please please take note that the angle is given in radians, so you must set your calculator in radians. Not to mention the fact that the inverse tangent of an angle is NOT another angle!!! So your answer wouldn't be in degrees anyway!

Last edited by mtb0minime (2006-12-13 11:52:51)

SplinterStrike
Roamer
+250|6846|Eskimo land. AKA Canada.

mtb0minime wrote:

Even though I gave him the answers, I agree with you. I'm just building him up so that when the test rolls around and he has no idea what to do because he was cheating on the homework, he'll fail and hopefully learn a lesson.

Plus I'm a super math nerd and couldn't help it anyway. And for you people contesting my answer for 1b, please please please take note that the angle is given in radians, so you must set your calculator in radians. Not to mention the fact that the inverse tangent of an angle is NOT another angle!!! So your answer wouldn't be in degrees anyway!
no wonder! I had my calculator in degrees. And yea...math geek 101 here. Can't resist solving things.
I miss having simple shit like that to do. Engineering is so freaking hard.
Chuckles
Member
+32|6983
Hopefully he goes in and gets some help from the teacher so he learns something other than how to get his homework done for him, and then passes the test.
tupla_s
.
+455|7027|Finland

mtb0minime wrote:

And for you people contesting my answer for 1b, please please please take note that the angle is given in radians, so you must set your calculator in radians. Not to mention the fact that the inverse tangent of an angle is NOT another angle!!! So your answer wouldn't be in degrees anyway!
1b is not an angle, wouldn't it be "tan 1,7601 = y" instead of "tan y = 1,7601" if it was an angle?

IMO it's
tan y = opposite / adjacent
tan y = 1,7601
tan-1 1,7601 = 60,4°
De_Jappe
Triarii
+432|6962|Belgium

It's 60.4° indeed.

Don't get suspended from school though.
Zimmer
Un Moderador
+1,688|7191|Scotland

De_Jappe wrote:

It's 60.4° indeed.

Don't get suspended from school though.
Says the guy who wants you to succeed in life.
Suspension is common, let him be.
Bullying is common, he rightfully defended his brother ( although beating up another child is not the answer )
And being shit at maths is common!
Gawwad
My way or Haddaway!
+212|7120|Espoo, Finland

tupla_s wrote:

mtb0minime wrote:

And for you people contesting my answer for 1b, please please please take note that the angle is given in radians, so you must set your calculator in radians. Not to mention the fact that the inverse tangent of an angle is NOT another angle!!! So your answer wouldn't be in degrees anyway!
1b is not an angle, wouldn't it be "tan 1,7601 = y" instead of "tan y = 1,7601" if it was an angle?

IMO it's
tan y = opposite / adjacent
tan y = 1,7601
tan-1 1,7601 = 60,4°
60,4° = ~1.0541 radians.
sneakysegan11
Member
+13|6979|York, PA

zimmer92 wrote:

De_Jappe wrote:

It's 60.4° indeed.

Don't get suspended from school though.
Says the guy who wants you to succeed in life.
Suspension is common, let him be.
Bullying is common, he rightfully defended his brother ( although beating up another child is not the answer )
And being shit at maths is common!
Thank you for being the only person who understands!!!! My brother is in 6th grade!!!!!!
13urnzz
Banned
+5,830|6932

SplinterStrike wrote:

Engineering is so freaking hard.
i work in a civil engineering firm.








as the p.c. technician...
JoeFriday
Git 'Er Dun
+23|6875|Canada
seems easy enough
heggs
Spamalamadingdong
+581|6823|New York

mtb0minime wrote:

Trig = easy shit. I took my differential equations final yesterday. You guys wanna try problems like:

Given the matrix
      -2  1  -1
A = 1  -3  0
      3  -5  0

i) find the eigenvalues
ii) for each eigenvalue find the algebraic and geometric multiplicities
iii) for each eigenvalue [lambda] find the smalles integer k such that the dimension of the nullspace of (A - [lambda]I)^k is equal to the algebraic multiplicty
iv) for each eigenvalue find q linearly independent generalized eigenvectors, where q is the algebraic multiplicity
v) verify that the collection of the generalized eigenvectors you find in part iv for all of the eigenvalues is linearly independent
vi) find a fundamental set of solutions for the system y' = Ay

Or how about...

given

y'' + 3y' + 2y = 3e^(-4t) , y(0) = 1, y'(0) = 0

find the homogenous equation, and then find the particular solution. Use these to find the general solution. Then find the solution satisfying the particular given initial conditions.

Cheers
haven't done this in a year or so.

don't have my diff eq text with me, and there isn't much on eigenvalues in FE review manual. so here's the second one.

homogeneous
y" + 3y' + 2y = 0

proceed with the characteristic eq:
r^2 + 2(1.5)r + 2 = 0   
a=1.5, b=2

roots are then: r = -1.5 +- sqrt((1.5^2)-2)
a^2 is greater than b (2.25 vs. 2), so the solution is y = C1(e^(r1*x)) + C2(e^(r2*x))

r1 =  -.7928 
r2 = 2.2071

added to solution : y =  C1(e^(-.7928x)) + C2(e^(2.2071x))


particular solution:
(may have done this wrong)

y = 3*C3(e^(-4t))     
y' = -12*C3(e^(-4t))
y" = 48*C3(e^(-4t))

subsituting into original equation(having done the work on paper):
48C3 - 36C3 + 6C3 = 3
C3 = .1667

complete solution:

y = y(h) + y(p)
y = C1(e^(-.7928x)) + C2(e^(2.2071x)) + .5e^(-4t)
y(0) = 1
C1+C2 = .5

y'(0) = 0
0 = -.7928C1 + 2.2071C2 - 2

after substituting and working it out.
C1 = -.7518
C2 = 1.2518

final solution:

y = -.7518(e^(-.7928x)) + 1.2518(e^(2.2071x)) + .5e^(-4t)

i may have made a mistake at the beginning by not dividing the 3 over to the other side. if that's the case, then the roots would be imaginary, changing the form of the solution.
Remember Me As A Time Of Day
Snowmanimal
Not so unique forum title
+30|6978|My head
I dont care if I give some kid the answers. I'd help any of you out with homework if need be. hah
mtb0minime
minimember
+2,418|7089

tupla_s wrote:

mtb0minime wrote:

And for you people contesting my answer for 1b, please please please take note that the angle is given in radians, so you must set your calculator in radians. Not to mention the fact that the inverse tangent of an angle is NOT another angle!!! So your answer wouldn't be in degrees anyway!
1b is not an angle, wouldn't it be "tan 1,7601 = y" instead of "tan y = 1,7601" if it was an angle?

IMO it's
tan y = opposite / adjacent
tan y = 1,7601
tan-1 1,7601 = 60,4°
Yeah, sorry about that. When I said 1b wasn't an angle, I wasn't thinking clearly and probably had a dislexic moment.

However, when it comes to the actual angle, you need to use radians because the problem was given to you in radians.


And boy, heggs, I'm impressed. I really didn't expect anyone to actually solve those, but good job!

Last edited by mtb0minime (2006-12-13 15:25:30)

Chuckles
Member
+32|6983

sneakysegan11 wrote:

Thank you for being the only person who understands!!!! My brother is in 6th grade!!!!!!
So, if an even bigger dude comes along, say the older brother of the "little freshman" you roughed up, and beats your ass around, that's cool too, right? 

I've got a little brother and sister too.  They both got picked on.  I was always able to defend them without beating anybody up though, and not, it's not because I can't handle myself. 

I just hate to see a kid that's obviously not the sharpest tool in the shed not working to better himself.  You'd all be doing him a bigger favor by teaching him how to do the work himself instead of giving him the answers.  This kid obviously needs all the mental stimulation he can get, including homework.  And kid, your teacher isn't the asshole.  If anything they're doing you a favor, and you're the asshole.
heggs
Spamalamadingdong
+581|6823|New York

mtb0minime wrote:

tupla_s wrote:

mtb0minime wrote:

And for you people contesting my answer for 1b, please please please take note that the angle is given in radians, so you must set your calculator in radians. Not to mention the fact that the inverse tangent of an angle is NOT another angle!!! So your answer wouldn't be in degrees anyway!
1b is not an angle, wouldn't it be "tan 1,7601 = y" instead of "tan y = 1,7601" if it was an angle?

IMO it's
tan y = opposite / adjacent
tan y = 1,7601
tan-1 1,7601 = 60,4°
Yeah, sorry about that. When I said 1b wasn't an angle, I wasn't thinking clearly and probably had a dislexic moment.

However, when it comes to the actual angle, you need to use radians because the problem was given to you in radians.


And boy, heggs, I'm impressed. I really didn't expect anyone to actually solve those, but good job!
thanks, graduated with a mechanical engineer degree. so i was basically 2 or 3 classes shy of having a math minor. i was kinda impressed myself by being able to finish it with a logical answer.
Remember Me As A Time Of Day
mtb0minime
minimember
+2,418|7089

Yeah, I'm also going to be a few classes shy of a math minor as well once I graduate. But I'd rather just graduate in 4 years instead of prolonging my stay

Board footer

Privacy Policy - © 2025 Jeff Minard