Question 1035120
Subtract 2<font face="symbol">p</font>

{{{9pi/2-2pi=9pi/2-4pi/2 = 5pi/2}}}

That's still not less than 2<font face="symbol">p</font>

So subtract 2<font face="symbol">p</font> again:

{{{5pi/2-2pi=5pi/2-4pi/2 = pi/2}}}

So {{{csc(9pi/2)=csc(pi/2)=1/sin(pi/2)=1/1=1}}}

Edwin</pre>