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FeelTheRT
10-22-2002, 07:18 PM
hey, i'm confused with some of the stuff here...

the direction says..
"Evaluate each expression in terms of radians."

the problems are..
1.) arc sin 1
2.) arc sin(-1)
3.) arc cos sqrt(3)/2

i dunno what to do! can someone help me plz?

DaosBeoulve
10-22-2002, 07:51 PM
arcsin is the same as the inverse sin. (same for arc cos, arctan, etc.)

Thus, you can just plug it into a calculator and get the answer, but that's too easy. Know anything about the unit circle? If so, then the first two are horribly easy.

Because I can't sit down and explain what the unit circle is to you firsthand, let's go about this a different way. At what radian measure does sin(theta)=1? Well, simple trig states that at pi/2 it would be one, thus arcsin(1) = pi/2. That's not the only answer, however. 5pi/2, 9pi/2 could also be answers.

Take it one step further (not sure exactly what you don't understand about the problem)--do you know what radians are? To convert from degrees to radians, use the simple factor (degrees)(pi/180) To convert from radians to degrees, use (radians)(180/pi). The use of radians or degrees is highly dependent on the situation and what exactly you want to use it for in the situation.

FeelTheRT
10-22-2002, 08:00 PM
i understand the vocabulary completely as well as the unit circle, however what is ti asking me? the directions say to Evaluate each expression in terms of radians. Does it want me to find the Domain and Range or something?

vf-xx
10-22-2002, 08:06 PM
no, it just means that you need to give your answer in radians, not degrees.

IE: pi, 2pi, 2/3pi...

pi/2 = 90deg
pi = 180 deg
2pi = 360 deg

see?

FeelTheRT
10-22-2002, 08:12 PM
LOL
HAHAHAHA

i must still have been under influence of my jack! I've been trying to graph these the whole time, thanx, i got it now.

:D

also.. just to make sure i'm doing this right.. the answer to #1 is pi/2 correct?