Polar coordinates, maximum distance.

In summary, the problem asks for the maximum distance of a point on the curve r=e^(\theta) from the line \theta=(pi/2). The solution involves rewriting x as e^(theta).cos(theta) and maximizing x, which is equal to r cos(\theta). This was initially misunderstood as the line \theta=pi/4 instead of \pi/2.
  • #1
xduckksx
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Homework Statement


The diagram (omitted) shows the curve C with polar equation r=e^(\theta), where 0\le\theta\le(pi/2). Find the maximum distance of a point of C from the line \theta=(pi/2), giving the answer in exact form.

The Attempt at a Solution



I'm not really sure how to attack this; it says in the examiners report that one needs to write x as e^(theta).cos(theta), but I can't see why this is...
 
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  • #2
The line [itex]\theta= \pi/2[/itex] is just the vertical line x= 0, the y-axis and the distance from any point (x, y) to that line is just x. And, of course, [itex]x= r cos(\theta)[/itex]. That is what you want to maximize.
 
  • #3
OMG I THOUGHT THE LINE WAS theta=pi/4 ... sigh...
 

1. What are polar coordinates?

Polar coordinates are a two-dimensional coordinate system that uses a distance from a fixed point (origin) and an angle from a fixed direction (usually the positive x-axis) to specify the location of a point. This is different from the traditional rectangular coordinate system, which uses x and y coordinates.

2. How do you convert between polar coordinates and rectangular coordinates?

To convert from polar coordinates to rectangular coordinates, you can use the formulas x = r * cos(theta) and y = r * sin(theta), where r is the distance from the origin and theta is the angle. To convert from rectangular coordinates to polar coordinates, you can use the formulas r = sqrt(x^2 + y^2) and theta = atan2(y, x).

3. What is the maximum distance in polar coordinates?

The maximum distance in polar coordinates is the distance from the origin to the farthest point on the coordinate plane. This distance is known as the radius, and it is infinite since there is no limit to how far a point can be from the origin.

4. How do you find the maximum distance in polar coordinates?

To find the maximum distance in polar coordinates, you can use the formula r = sqrt(x^2 + y^2). This formula calculates the distance from the origin to any point on the coordinate plane. To find the maximum distance, you can plug in different values for x and y and see which combination results in the largest value for r.

5. What is the significance of maximum distance in polar coordinates?

The maximum distance in polar coordinates is significant because it helps us understand the shape and size of a polar coordinate plane. It also allows us to plot points and draw curves accurately. Furthermore, the maximum distance can be used to calculate the area and circumference of polar shapes like circles and spirals.

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