Is this a poorly worded question?

**rockyshephear** · Jun16-09, 11:15 PM

Example found on a website...(there were no graphs or explanations as to p or r or q)
Reverse engineering the question from the answer, I found p to be 180.
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A vector that has length 10 makes an angle of p/6 with the x-axis. Find its components.

Solution:

x = r cos q, y = r sin q

So that

x = (10)(/ 2), y = 10 (1/2) = 5

We can write the vector as

5 i + 5j

**slider142** · Jun16-09, 11:23 PM

They are using radian measure, and they meant p = $LaTeX Code: \\pi$ radians which is equivalent to 180 degrees. Radian measure is derived from the unit circle; the radian measure of an angle is given by the length of arc that the angle subtends on a unit circle centered at the vertex of the angle. this makes use of the derived fact that the circumference of a circle is known to be 2 $LaTeX Code: \\pi$ , so that 360 degrees is 2 $LaTeX Code: \\pi$ radians. It is common to leave off the "radian" as a unit of measure since it is also defined as a dimensionless ratio of two lengths (the length of arc divided by the length of the radius of the circle).

**rockyshephear** · Jun16-09, 11:30 PM

Thanks

**Tibarn** · Jun17-09, 12:47 AM

Solution:

x = r cos q, y = r sin q

So that

x = (10)(/ 2), y = 10 (1/2) = 5

We can write the vector as

5 i + 5j

Is it just me, or does that vector have neither the length nor the angle specified in the original problem?

**Irrational** · Jun17-09, 04:09 AM

yeah. answer is $LaTeX Code: 5\\sqrt{3}i + 5j$

$LaTeX Code: \\cos (\\frac {\\pi}{6}) = \\frac{\\sqrt3}{2}$