Differential Equation: Solving for x in terms of θ | (3+cos2θ)dx/dθ = xsin2θ

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SUMMARY

The discussion focuses on solving the differential equation (3 + cos 2θ) dx/dθ = x sin 2θ. The correct approach involves separating variables, leading to the integral dx/x = (sin 2θ)/(3 + cos 2θ) dθ. A u-substitution is applied with u = (3 + cos 2θ), resulting in du/dθ = -2 sin 2θ. The steps taken are confirmed as correct, allowing for further solution development.

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  • Understanding of first-order separable differential equations
  • Knowledge of u-substitution in integration
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chwala
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Homework Statement


Solve and obtain an expression for x in terms of θ given ## (3+ cos 2θ) dx/dθ = x sin 2θ##

Homework Equations

The Attempt at a Solution


...##dx/x = ((sin 2θ)/(3+ cos 2θ))dθ## ,

let ##u = (3+cos 2θ)⇒ du/dθ= -2 sin 2θ##
thus

##∫dx/x = -1/2∫du/u ##...[/B]are my steps correct?i can solve from here
 
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You noticed that it was 1st order seperable, and proposed a u-substitution for the resulting RHS: well done.
I didn't check your arithmetic - you have to do that yourself - but the reasoning is sound so far.
 
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