Michigan State University - Diagnostic Exam

6.18

  •   Find a =  cosθ  and b = sin θ  where θ  is the angle shown in the sketch below.

    PIC

    a)       √ --
a = -   3, b = 1  b)             √--
     1       3
a =  -, b = ----
     2       2  c)      √--
      3      1
a =  ---, b =--
     2       2
         
    d)     - √3--     1
a = -----, b = --
      2        2  e)     1      - √3--
a = --, b =-----
    2        2

Solution:

PIC

Notice that the distance from the origin to   √ --
(-  3, 1)  (shown in red) has length ∘  (√--)2-----
      3  +  12 = 2  . It follows that

              √ --
            ----3                 1-
a = cos θ =   2   and b = sinθ =  2

Diagnostic:

If you miss this question please review trigonometric functions of any angle.


July 15, 2008