What are the components of the vector between the origin and the polar coordinate (12, (7pi)/8)(12,7π8)?

1 Answer
Feb 29, 2016

( -12 cos piπ/8, 12 sin piπ/8 ) =
( -6sqrt(2 + sqrt2 ). 6sqrt(2 - sqrt2 )
= ( -11.09, 4.59 ), nearly.

Explanation:

Components of radius vector to ( r, thetaθ ) are ( r cos thetaθ, r sin thetaθ )
cos (piπ - thetaθ ) = - cos thetaθ
sin (piπ - thetaθ ) = sin thetaθ
cos piπ/8 = sqrt((1 + cos piπ/4)/2)
sin piπ/8 = sqrt((1 - cos piπ/4)/2)