Question 715378
<pre>
What are the exact values of the six trig functions of &#1012; 
when the cot(&#1012;) is undefined and cos(&#1012;) < 0? 

cot(&#1012;) = {{{x/y}}} which is undefined when y=0, which are at the 
unit circle points (0,0), where &#1012; = 0 and (-1,0) where &#1012; = &#960;.
cos(0) = 1 and cos(&#960;) = -1, so since cos(&#1012;) is < 0, &#1012; must be &#960;.
r = 1 on the unit circle:

sin(&#960;) = {{{y/r}}} = {{{0/1}}} = 0 
cos(&#960;) = {{{x/r}}} = {{{(-1)/1}}} = -1
tan(&#960;) = {{{y/x}}} = {{{0/(-1)}}} = 0
sec(&#960;) = {{{r/x}}} = {{{1/(-1)}}} = -1
csc(&#960;) = {{{r/y}}} = {{{1/0}}} = undefined
cot(&#960;) = {{{x/y}}} = {{{(-1)/0}}} = undefined.

Edwin</pre>