Chapter 9: Problem 17
Find the foci and vertices of the ellipse, and sketch its graph. $$ 4 x^{2}+9 y^{2}=36 $$
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Chapter 9: Problem 17
Find the foci and vertices of the ellipse, and sketch its graph. $$ 4 x^{2}+9 y^{2}=36 $$
These are the key concepts you need to understand to accurately answer the question.
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Let \(\psi\) be the angle between the radial line \(O P\) and the tangent line to the curve with polar equation \(r=f(\theta)\) at \(P\) (see the figure). Show that $$ \tan \psi=r \frac{d \theta}{d r} $$ Hint: Observe that \(\psi=\phi-\theta\). Then use the trigonometric identity $$ \tan (a-b)=\frac{\tan a-\tan b}{1+\tan a \tan b} $$
Sketch the curve with the polar equation. \(r=e^{\theta}, \quad \theta \geq 0 \quad\) (logarithmic spiral)
Show that a conic with focus at the origin, eccentricity \(e\), and directrix \(x=d\) has polar equation $$ r=\frac{e d}{1+e \cos \theta} $$
a. Plot the graphs of the cardioids \(r=a(1+\cos \theta)\) and \(r=a(1-\cos \theta)\). b. Show that the cardioids intersect at right angles except at the pole.
Find the slope of the tangent line to the curve at the point corresponding to the value of the parameter. $$ x=e^{2 t}, \quad y=\ln t ; \quad t=1 $$
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