What is the distance between (1 ,(3 pi)/4 )(1,3π4) and (2 , (15 pi )/8 )(2,15π8)?

1 Answer
Dec 2, 2016

d~~2.95d2.95

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 (1,(3pi)/4)(1,3π4) and (2,(15pi)/8)(2,15π8), 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((1)^2+(2)^2-2*1*2cos((15pi)/8-(3pi)/4))d=(1)2+(2)2212cos(15π83π4)

:. d~~2.95