Orthogonal Trajectory. Calc IV.

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SUMMARY

The discussion focuses on finding orthogonal trajectories for the equations y=cln(x), y=ce^x, and y=sin(x)+cx^2. The first two trajectories were approached using integration by parts and separation of variables, yielding solutions involving logarithmic and exponential functions. The third trajectory, however, presents challenges due to its complexity, particularly in the differentiation and integration steps. The user seeks guidance on progressing from their current solution attempts.

PREREQUISITES
  • Understanding of differential equations and orthogonal trajectories
  • Proficiency in integration techniques, including integration by parts
  • Familiarity with logarithmic and exponential functions
  • Basic knowledge of trigonometric functions and their derivatives
NEXT STEPS
  • Study the method of finding orthogonal trajectories in differential equations
  • Practice integration by parts with various functions
  • Explore advanced techniques for solving non-linear differential equations
  • Review the properties and applications of trigonometric functions in calculus
USEFUL FOR

Students in Calculus IV, particularly those studying differential equations, as well as educators looking for examples of orthogonal trajectories and integration techniques.

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Homework Statement



Find orthogonal trajectories for y=clnx, y=cex, y=sin(x)+cx

Homework Equations



Simple integration for the most part.

The Attempt at a Solution



I'm fairly confident on the first two, its the third that's giving me trouble.

First, y=cln(x)
c=\frac{y}{ln(x)}
\frac{dy}{dx}=\frac{c}{x}
\frac{dy}{dx}=\frac{y}{xln(x)}=m1
\frac{dy}{dx}=\frac{-xln(x)}{y}=m2
\int-xln(x)dx=\intydy using IBP
\frac{-lnxx^2}{2}-\int\frac{-x}{2}dx
c+\frac{-lnxx^2}{2}+\frac{x^2}{4}=\frac{y^2}{2}

Second, y=cex
c=\frac{y}{e^x}
\frac{dy}{dx}=cex
\frac{dy}{dx}=\frac{e^xy}{e^x}=y=m1
\frac{dy}{dx}=\frac{-1}{y}=m2
\intydy=\int-1dx
\frac{y^2}{2}+x=c

Third, y=sin(x)+cx2
c=\frac{y-sin(x)}{x^2}
\frac{dy}{dx}=cos(x)+2xc
\frac{dy}{dx}=cos(x)+\frac{2(y-sin(x))}{x}

I've been unable to make any more progress.
 
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Can nobody give me an idea of where I should go from here? I don't know if I'm having a simple algebra problem or what.
 
Why won't anyone help me?! I need to know how to solve this problem before class!
 

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