Matematika/Lanko ilgis: Skirtumas tarp puslapio versijų

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50 eilutė:
:<math>=\sqrt{\left(\frac{d\rho}{d\theta}\cos\theta-\rho\sin\theta\right)^2+\left(\frac{d\rho}{d\theta}\sin\theta+\rho\cos\theta\right)^2}d\theta =</math>
:<math>=\sqrt{\left[\left(\frac{d\rho}{d\theta}\right)^2\cos^2\theta-2\rho\frac{d\rho}{d\theta}\sin(\theta)\cos(\theta)+\rho^2\sin^2\theta\right]+ \left[\left(\frac{d\rho}{d\theta}\right)^2\sin^2\theta+2\rho\frac{d\rho}{d\theta}\sin(\theta)\cos(\theta)+\rho^2\cos^2\theta\right]}d\theta =</math>
:<math>=\sqrt{\left(\frac{d\rho}{d\theta}\right)^2\cos^2\theta+\rho^2\sin^2\theta+ \left(\frac{d\rho}{d\theta}\right)^2\sin^2\theta+ \rho^2\cos^2\theta} \; d\theta =</math>
:<math>=\sqrt{\left(\frac{d\rho}{d\theta}\right)^2+\rho^2} \; d\theta .</math>