Question 1157771
a) Since {{{ x=r*cos(theta)}}} and {{{y=r*sin(theta)}}}, we have {{{x=3*cos(5*pi/6)=3*(-sqrt(3)/2)=(-3*sqrt(3))/2}}} and {{{y=3*sin(5*pi/6)=3*1/2=3/2}}}. So the coordinates are {{{(-(3*sqrt(3))/2)}}},{{{3/2}}}.
b) {{{x=cos(pi/2)=0}}} {{{y=sin(pi/2)=1}}} The coordinates are (0,1).
c){{{x=3*cos(11*pi/18)}}},{{{y=3*sin(11*pi/18)}}}