#P_A=(-6,pi/2)#
#r_A=-6#
#(r_A)^2=36#
#theta_A=pi/2#
#P_B=(5,pi/12)#
#r_B=5#
#(r_B)^2=25#
#theta_B=pi/12#
#alpha=theta_B-theta_A=pi/12-pi/2#
#alpha=(2pi-12pi)/24=-(10pi)/24=-(5pi)/12#
#"distance between two points in the polar coordinate system is given as:"#
#Delta s=sqrt(r_A^2+r_B^2-2*r_A*r_B*cos alpha)#
#Delta s=sqrt(36+25-2*6*5*cos(-(5pi)/12))#
#Delta s=sqrt(61-60*0.26)#
#Delta s=sqrt(61-15.6)#
#Delta s=6.74 " "unit#