d=√r21+r22−2r1r2cos(ϕ2−ϕ1)
d=√62+22−2⋅6⋅2⋅cos(−3π8−7π12)
d=√40−24⋅cos(−29π24)
d=2√10−6cos(29π24)
cos(29π6)=cos(4π+5π6)=cos(5π6)=−√32
cos(29π12)=cos(29π62)=
⎷1+cos(29π6)2
cos(29π12)=√1−√322=√2−√34=√2−√32
cos(29π24)=cos(29π122)=
⎷1+cos(29π12)2
cos(29π24)=
⎷1+√(2−√3)22
cos(29π24)=√2+√2−√32
d=2
⎷10−6⋅√2+√2−√32
d=2√10−3√2+√2−√3