Compute the modulus and argument of each complex number?

a. -5i

b. sqrt10 (cos(5pi/7) + isin(5pi/7))

Answer and Explanation:

To find : Compute the modulus and argument of each complex number?

Solution :

a)

When the complex number is in the form

Then the modulus of z is and argument is

On comparing with given complex number, a=0 and b=-5

Substitute in formulas,

The modulus of z is

The argument of z is

b)

When the complex number is in the polar form

Then the modulus of z is r and argument is .

On comparing with given complex number,

The modulus of z is

The argument of z is

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step-by-step explanation: