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") #