Recent content by vipertongn

I hate to bring up an old thread, but I'm reviewing this and i haven't gotten the answer for the last two really. What is the probability that there would be no water rationing in the next ten years? ok, I think for this case I calculate it first the probability of it actually not occurring...

Water shortages require water rationing policies. From past records, we know that the probability that water needs to be rationed in a southland water district in any given year is 0.15. Assume that water rationing in consecutive years are independent events. Let X be the number of years with...

yea but the overall equation still doesn't make out to be 419 as shown in the solutions

I'm not sure about that, i used 50 degrees because i set the x-axis to be the same as the block, and then used the transversal angles are equal...so adding 20 to 30 degrees to get that. It's ironic because when I solved for the motion...it came to the correct answer of 301, but for the first...

ohh it was drawn wrong...ok the new angle for P is 50 degrees from the horizontal of my new axis. I made my new equation to be P= ma+mg(sin20+ mu cos20) ----------------------------------------------- cos50- mu sin 50

Homework Statement A 20-kg package is at rest on an incline when a force P is applied to it. Determine the magnitude of P if 10s is required for the package to travel 5m up the incline. The static and kinetic coefficients of friction between the package and the incline are both equal to 0.3...

Ok so I have something like this...not drawn to scale http://i53.tinypic.com/303l5k6.gif I can see that with the law of cos I can get 49N However...with this other method where you set Sum of F=0 With sqrt(Fx^2+Fy^2)=R sqrt((40*cos(20)+20*cos(30))^2+(40*sin(20)-20*sin(30))^2) I...

Homework Statement Find the recurrence relation for the following differential equation. You do not need to solve the rest of the way. y" − 2xy = 0 The Attempt at a Solution I'm not exactly sure how to do this problem but from the example of the book I tried this: y"-2xy= \sum...

Homework Statement solve using undetermined coeffecients y"+3y=-48x^2e^(3x) Homework Equations x^2e^3x gives a Yp=(Ax^2+Bx+C)e^3x The Attempt at a Solution I can get yc easily which is yc=cos(sqrt(3x))+sin(sqrt(3x)) However, I'm not sure as to how to set it up so that...

however, in my solutions manual it says the solution comes out to be xe^2x, and I have no idea how that came to be. except for the use of this equation y2=y1S e^(-SP(x)dx)/y1^2 dx

ahh...so then u"=0 makes u'=c and then later u=xc1+c2 and y2=uy1 y2=xc1*e^2x+c2*e^2x but what then? how do I solve for c1 and c2?

Homework Statement solve y"-4y'+4y=0 y1=e^(2x) using reduction of order The Attempt at a Solution y2=uy=ue^2x y2'=u'e^2x+2ue^2x y2"=u"e^2x+4u'e^2x+4ue^2x I then substitute that into the original equation to get u"e^2x+4u'e^2x+4ue^2x-4u'e^2x-8ue^2x+ue^2x=0 simplify to get...

xdy/dx+y=1/y^2:using substitution in differential eq Homework Statement solve using substitution xdy/dx+y=1/y^2 The Attempt at a Solution Thanks to the people who've help me thus far. here's a bernulli problem that I'm having. I change this problem around to... dy/dx=y^3/xy^2...

wel i know i could have dy/dx = x-y^2/2y But I still don't know which method to solve this. if i try substitution it doesn't work... Ok I tried this I substituted u=y^2 du=2ydy 2ydy=(x-y^2)dx du=(x-u)dx du/dx+u=x Makes a Linear Eq p(x)=1 f(x)=x e^integral(1)dx = e^x...

Thanks, now I'm trying to figure out a new problem (didn't want to make another post) y'+y/2=x/2y. I'm trying to figure out what would be a good method to solve this. Any suggestions? I ruled out exact. It looks like a linear equation kinda...but I'm not sure