Solving a Separable ODE: y'+ytanx=cosx with Initial Condition y(0)=1

eeriana
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Homework Statement


y'+ytanx = cos x y(0)=1


Homework Equations





The Attempt at a Solution



We are studying separable ode's and integrating factor right now, I am a little confused... If someone could steer me in the right direction, it would be greatly appreciated... This is what I have so far:

P= tanx
\intP = -ln|cosx|
\mu=e^{}-lncosx
\mu= 1/cosx

(1/cosx*y)' =\int1/cosx cosx

and this is where I get stuck... am I even on the right track?

Thanks

Eeriana
 
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You are on the right track and have calculated the IF correctly and written the complete differential correctly. Note that you can simplify the integrand...
 
But isn't 1/cosx * cosx = 1 Or am I having an algebraic malfunction?
 
eeriana said:
But isn't 1/cosx * cosx = 1 Or am I having an algebraic malfunction?
Nope you are indeed correct.
 
I thought I was doing something wrong... hmmm..now I am going to see if I can finish it!

Thanks for the help
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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