Expert: Sherry Wallin - 1/4/2010

Question
I need to find the ArcCos1, ArcSin(-1/2), and ArcTan(-radical3/3)
I have more problems but dont wanna bother. These would be much help. Thanks

Answer
Melisa~
    When you take the arcsin x or the arccos x or the arctan x you are asking yourself what angle gives the value of x. For example for the arccos 1 you want to know the cos of what angle has a value of 1? nd the answer is when the angle is 0 or 2pi or any multiple of 2pi. For the arcsin(-1/2) ask yourself what angle is the sin of the angle equal to -1/2. The sin of 30 deg is 1/2 so you want the reference angle for 30 deg which is either 210 deg or 330 deg(This is where y is a negative number). So for the arctan[(-sqrt3)/3] what angle is the tangent -sqrt3/3??

Math Prof