Integrating Int((5+10y^4)dy/(y+2y^5)) - A Step-by-Step Guide

  • Thread starter Thread starter marmot
  • Start date Start date
  • Tags Tags
    Integrating
marmot
Messages
55
Reaction score
1

Homework Statement



I want to deal with this int((5+10y^4)dy/(y+2y^5))

Homework Equations



integration, substitution, partial fractions?


The Attempt at a Solution



I tried a bunch of random things. I think it hs to do with substitution because if I make u=y+2y^5, du/dy=1+10y^4 which is strikingly similar to the numerator, so there must be a cancellation. this integral is part of a dif equation, but i can't see to go past this! i know for sure this is the correct set up because i used my calculator to integrate and it solved the differential equation.
 
Physics news on Phys.org
Uh, the ratio of those two polynomials is a VERY SIMPLE THING. Can you find it? Factor them.
 
Try this :
5 + 10y^4 = 4 + 1 + 10y^4

after you get it, think of a crafty substitution
 
aostraff said:
Try this :
5 + 10y^4 = 4 + 1 + 10y^4

after you get it, think of a crafty substitution

Think of a crafty cancellation before you do the crafty substitution.
 
jesus i feel like a complete retard. i hate when i don't get something as obvious.i factored both and canceled that nasty factor and then everything went smooth, thanks a bunch gentlemen.
 
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