Complex Numbers Warmup

• 5i
• -5i
• 5+i
• -5

• 10
• -10
• 10i
• -10i

What is the complex conjugate of  4-3i?

• A.  1/(4-3i)

• B. 1/(4+3i)

• C.  -4 + 3i

• D.  4 + 3i

Answer explanation

The complex conjugate of a complex number a + bi is a - bi. For 4 - 3i, the conjugate is 4 + 3i, which corresponds to choice D.

What does i² equal?

• -1

• √-1

• 1

• -√1

Answer explanation

i is defined as the imaginary unit, where i^2 = -1. Therefore, the correct answer is -1.

What letter represents an imaginary number?

• a

• i

• j

• x

Answer explanation

The letter 'i' represents the imaginary unit in mathematics, defined as the square root of -1. It is commonly used in complex numbers, distinguishing it from other letters like 'a', 'j', or 'x'.

• True

• False

Answer explanation

The statement is true because i, defined as the square root of -1, is the fundamental imaginary unit in mathematics. It is used to extend the real number system to complex numbers.

• the complex conjugate

• -9i

• the imaginary unit

• 7

• the real part

• the imaginary part

• 7+9i