00:01
Okay, so i'm solving this problem involving a circle of a radius of 3 cm.
00:10
And the terminal angle on the circle is at 2 .7 radian.
00:16
Okay, so this is 2 .7 radian.
00:20
And we're finding x and y in both radian and a centimeter.
00:23
So first, to find x, which is the distance from the terminal point to the right of the center of the circle.
00:32
Okay so to find x in radian first you must realize that 3 centimeter is one radius length which is 1 radiant okay so so what we have here is that this is a right triangle and the angle inside you can call that theta or whatever you know, the angle.
01:11
So, data is equal to 180, which is pi in radiance minus 2 .7.
01:23
Okay, so that's how you find data.
01:26
All right, so to find x, you can use the sokatoa trick functions.
01:35
So cosine of data equals x.
01:40
3 centimeter, which is x over 1 radian, because 3 centimeter is one radiance length, so x over 1.
01:49
Basically, so cosine theta equals x, okay? and cosine theta is the same thing as cosine of pi minus 2 .7.
02:05
So using the fact that the cosine ratio is symmetrical, the cosine is symmetrical through the y -axis since if you have cosine of something that is reflected through the y -axis, an angle that's reflected, it's the same is the negative of the positive cosine.
02:34
So if theta 1 was here, then cosine of theta 1 equals the opposite of the the 1 equals the opposite of of cosine of theta since they're on opposite size of the y -axis so they're reflected like that okay so cosine of theta is cosine of pi minus 2 .7 which is the same thing as negative of cosine of 2 .7 okay okay so that so if you put that in your calculator make sure you're on radiant mode you can get the answer for your x in radiance.
03:15
So 2 .7, take the cosine, depends on your calculator.
03:21
Times negative 1 is going to give you 0 .904...