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**lakitu****Member**- Registered: 2006-03-08
- Posts: 5

My teacher has told me I will need to be able to do these in my up and comping exam later this month. He covered the topic a while ago but I didn't quite understand. Here is an example I have.

Express the polar point (6, 120 °) in rectangular coordinates.

I have no idea how to start doing these? Guidence of any kind would be wonderful.

Regards Lakitu

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**mikau****Member**- Registered: 2005-08-22
- Posts: 1,504

Ok, basicly polar form locates a point by giving the distance and angle to the point, in relation to the origin. Rectangular coordinates loctate a point by its horizontal and vertical distance from the origin. Hopefully this diagram will help.

You have a length of 6 at an angle of 120 degrees. To describe the point in rectangular form, you need to find the horizontal and vertical distance from the origin. Here, you can draw a 60 degree right triangle with a hypotenuse of 6 units. So all you have to do is find the length of the horizontal and vertical sides to get the horizontal and vertical distance from the origin. You can do this using similar triangles or trig functions (sine and cosine). Also note, in this example, the horizontal side of the triangle I drew, will have a length of 3, however, this is 3 units to the LEFT of the origin, therefore its x coordinate will be -3 and not 3.

A logarithm is just a misspelled algorithm.

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**lakitu****Member**- Registered: 2006-03-08
- Posts: 5

Thank you Mikau,

Your post was incrdibly helpful! I understand it all now thank you for doing the diagrams also.

Kind Regards

Lakitu

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**mikau****Member**- Registered: 2005-08-22
- Posts: 1,504

Happy to be of assistance! :-)

A logarithm is just a misspelled algorithm.

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