What is the distance between (-3 ,(5 pi)/6 )(3,5π6) and (-1 , (11 pi )/12 )(1,11π12)?

1 Answer
Nov 30, 2016

d~~4.20d4.20

Explanation:

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

So lets call the coordinates of P_1P1 as (r_1,theta_1)(r1,θ1) and coordinates of P_2P2 as (r_2,theta_2)(r2,θ2) . 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))d=(r1)2+(r2)22r1r2cos(θ2θ1)

Thererfore using the points (-3,(5pi)/6)(3,5π6) and (-1,(11pi)/12)(1,11π12), and the formula

d=sqrt((r_1) ^2+(r_2)^2-2r_1r_2cos(theta_2-theta_1))d=(r1)2+(r2)22r1r2cos(θ2θ1)

we have

d=sqrt((-3)^2+(-1)^2-2*-3*-1cos((11pi)/12-(5pi)/6))d=(3)2+(1)2231cos(11π125π6)

:. d~~4.20