SOLUTION: What is {{{ cos(t) }}}if {{{ t }}} corresponds to the point (-2, 0)? A.) {{{ 0 }}} B.) {{{ 1 }}} C.) {{{ -1 }}} D.) Undefined.

Algebra ->  Test -> SOLUTION: What is {{{ cos(t) }}}if {{{ t }}} corresponds to the point (-2, 0)? A.) {{{ 0 }}} B.) {{{ 1 }}} C.) {{{ -1 }}} D.) Undefined.       Log On


   

Question 1058523: What is +cos%28t%29+if +t+ corresponds to the point (-2, 0)?
A.) +0+
B.) +1+
C.) +-1+
D.) Undefined.
Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
The angle indicated by the red arc is 180° or p radians.



But the right triangle is "smashed" flat against the x-axis,
so its hypotenuse coincides with its horizontal side, and
its vertical side is 0. 

The adjacent side is the x coordinate of the point -2.
The hypotenuse r, is the radius vector which coincides 
with the green line.  Since hypotenuse or radius vector
is always taken positive, its value is +2

cos%28%22180%B0%22%29%22%22=%22%22x%2Fr%22%22=%22%22%28-2%29%2F%28%22%22+%2B+2%29%22%22=%22%22-1

Edwin