Various DE problems and related stuff - help

  • Thread starter Thread starter WirelesssTouc
  • Start date Start date
WirelesssTouc
Messages
1
Reaction score
0
My DE class has been 100% about solving equations giving an equation. But my teacher seems to think giving us a very wordy sheet of homework would be fun and I just seem to be very lost. Trying to go through this systematically starting with the first problem and I've no idea what to do.

I have to draw a direction field. I figured I could plug in various values of x and t to just get dx/dt, but I don't know what to do about the other variables, r, b, and a. Can I simply set r=1, a=1, and b=0, arbitrarily, since they would be random constants in the logistics equation in the first place? So lost.

Attached is all the assignment.
 

Attachments

  • lastscan.jpg
    lastscan.jpg
    46.2 KB · Views: 375
Physics news on Phys.org
Yes, a, b, and r are constants. I would be a little careful about setting any constant to 0. That may remove important parts of the equation and so not be as general as you would like to.
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
Back
Top