What is the distance between #(-3 , (19 pi)/12 )# and #(-1 , pi/4 )#?

1 Answer
Dec 1, 2016

#d~~3.61#

Explanation:

Each point on a polar plane is represented by the ordered pair #(r,theta)#.

So lets call the coordinates of #P_1# as #(r_1,theta_1)# and coordinates of #P_2# as #(r_2,theta_2)# . To find the distance between two points on a polar plane use the formula #d=sqrt((r_1) ^2+(r_2)^2-2r_1r_2cos(theta_2-theta_1))#

Thererfore using the points #(-3,(19pi)/12)# and #(-1,(pi)/4)#, and the formula

#d=sqrt((r_1) ^2+(r_2)^2-2r_1r_2cos(theta_2-theta_1))#

we have

#d=sqrt((-3) ^2+(-1)^2-2*-3*-1cos((pi)/4-(19pi)/12))#

#:. d~~3.61#