Question

Find the rectangular coordinates of the point that has polar coordinates , 4, −3π/4

Answer 1

hello :
x= r cosθ
y= r sinθ
r = 4 and θ = −3π/4
cos( −3π/4 ) = cos( 3π/4 ) = cos ( π - π/4) = - cos (π/4)= - √2/2
sin( −3π/4 ) = - sin( 3π/4 ) = - sin ( π - π/4) = -sin (π/4)= - √2/2
x = - 2 √2
y = - 2 √2