What is the distance the polar coordinates #(-2 ,( -3 )/8 )# and #(4 ,(-7 pi )/4 )#?

1 Answer
Feb 21, 2018

Distance between the polar coordinates #color(brown)(d = 5.9066#

Explanation:

Using distance formula for polar coordinates,

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

Given #r1 = -2, theta _1 = -(3/8), r_2 = 4, theta_2 = -((7pi)/4)#

Substituting the values in the formula,

#d = sqrt(-2^2 + 4^2 - (2 (-2) (4) cos (-(3/8) - ((-7pi)/4))#

#d = sqrt (4 + 16 +16 cos((14pi - 3)/8)#

#d = sqrt(20 + 16cos ((14pi - 3)/8) )= 5.9066# units