Question

Is 3i a complex number

Answer 1

Remember that a complex number has the form a + bi. You need to figure out what a and b need to be. Since −3i is an imaginary number, it is the imaginary part (bi) of the complex number a + bi. This imaginary number has no real parts, so the value of a is 0.

Answer 2

ANSWER

Yes

EXPLANATION

The number

$3i$

can be rewritten as

$0 + 3i$This is of ty form

$z = a + bi$

where 0 is the real part and 3i is the imaginary or complex part.

$3i$

is therefore a complex number. It is purely imaginary because the real part is zero.