What is the distance between #(1 ,( pi)/4 )# and #(-1 , ( 3 pi )/2 )#?

1 Answer
Mar 27, 2016

#s=0,77" unit"#

Explanation:

#"use the formula :" s=sqrt(r_1^2+r_2^2-2*r_1*r_2*cos(theta_2-theta_1))#
#"the form of the polar coordinate:"#
#P_1=(r_1,theta_1)#
#P_2=(r_2,theta_2)#
#P_1=(1,pi/4)#
#P_2=(-1,(3pi)/2)#
#theta_2-theta_1=(3pi)/2-pi/4)=(5pi)/4#

#s=sqrt(1^2+(-1)^2+2*1*1*cos (5pi)/4)#

#s=sqrt(1+1+2*(-0,707)#
#s=sqrt(2-1,414)#
#s=sqrt(0,586)#
#s=0,77#