How do you express 1 – 3i in polar form?

1 Answer
Jan 23, 2016

(sqrt10 , - 1.25 )

Explanation:

Using the formulae that links Cartesian to Polar coordinates.

• r^2 = x^2 + y^2

• theta = tan^-1 (y/x )

[ 1 - 3i is in 4th quadrant and care must be taken to ensure

that theta is in the 4th quadrant ]

(Here x = 1 and y = - 3 )

r^2 = 1^2 + (-3)^2 = 1 + 9 = 10

rArr r = sqrt10

and theta = tan^-1 (-3) = - 1.25 color(black)("radians" )

theta = - 1.25 color(black)(" is in the 4th quadrant")