Question 544936
If the cofunction of an angle is the function of its complement, all you have to do in each case is find the angle that woould add to 90 degrees or {{{pi/2}}} radians.
a) for {{{pi/6}}} the angle you are looking for is {{{pi/2-pi/6=pi/3}}}, so
{{{sin(pi/6)=cos(pi/3)}}}
Those are angles you should be familiar with {{{pi/6=30degrees}}}, {{{pi/3=60degrees}}}, and {{{sin(30degrees)=cos(60degrees)}}}
b) cot(1 radian)?  or is it cot(1 degree)?
{{{cot(1 degree)=tan(89degrees)}}}
if in radians, {{{cot(1)=tan(pi/2-1)}}}
c) cos(90 degrees)=sin(0 degrees)
d) 90 degrees - (80 degrees -x)= 90 degrees - 80 degrees +x=10 degrees +x
csc (80 degrees -x)=sec (10 degrees +x)