What is the distance between (-9 ,( 17 )/12 )(9,1712) and (-2 ,( 5 pi )/4 )(2,5π4)?

1 Answer
Nov 30, 2016

see below

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 (-9,17/12)(9,1712) and (-2,(5pi)/4)(2,5π4), 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((-9) ^2+(-2)^2-2*-9*-2cos((5pi)/4-17/12))d=(9)2+(2)2292cos(5π41712)

:. d~~10.68