Bit of a problem with polar coordinates.

AI Thread Summary
The discussion revolves around converting polar coordinates to rectangular coordinates using the formulas x = r cos(Theta) and y = r sin(Theta). The user is working with the polar point (rad2, 4.39) but is getting incorrect results due to their calculator being set to degree mode instead of radian mode. They realize that to convert radians to degrees, they can multiply by 180/pi. The user expresses relief at discovering the solution to their problem. Proper calculator settings are crucial for accurate trigonometric calculations.
kryptos
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Bit of a problem with polar coordinates. (Only trig knowledge needed.)

Right. So, in this problem, I'm given the polar coordinate point (rad2, 4.39) -- "rad2" being, naturally, short for radical 2. I'm to find the rectangular coordinates of the point, using the formulas:

x = r cos Theta

and y = r sin Theta. In this problem, r = rad2 and Theta = 4.39.

Simple, no? Only for some reason, it's not coming out right with my calculator. I substitute the givens, for:

x = rad2 * (cos 4.39)

and y = rad2 * (sin 4.39).

I have the answers -- they're in the back of the textbook -- but can't figure out the process. x should equal approx. -0.45, and y should equal -1.34. Instead, I find x to equal 1.41 and y to equal 0.11. Am I doing something in the wrong order?

Any help is appreciated. Thanks. ; )
 
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Are you sure your calculator is in radian mode and not degree mode if the 4.39 is inradians?
 
Actually, no. I hadn't thought of that. But I don't know how to set it in radian mode. Is there some way I could convert the 4.39 into a form usable in degree mode?
 
kryptos said:
Actually, no. I hadn't thought of that. But I don't know how to set it in radian mode. Is there some way I could convert the 4.39 into a form usable in degree mode?

Multiply by 180/pi.
 
d_leet said:
Multiply by 180/pi.

. . . . . . . .

*smacks forehead*

I can't believe I missed that. Thanks so much.
 
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