What is the distance between (2 ,(7 pi)/6 )(2,7π6) and (-7 , (- pi )/4 )(7,π4)?

1 Answer
Dec 1, 2016

d~~6.76d6.76

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 (2,(7pi)/6)(2,7π6) and (-7,(-pi)/4)(7,π4), 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((2) ^2+(-7)^2-2*2*-7cos((-pi)/4-(7pi)/6))d=(2)2+(7)2227cos(π47π6)

:. d~~6.76