Using Expressions with Complex Numbers - Math

Multiplying top and bottom by the complex conjugate eliminates i from the denominator

Use FOIL to multiply. We can treat as a variable for now, just as if it were an .

Combine like terms.

Now we can substitute for .

Simplify.

We will need to simplify the rational expression by removing imaginary terms from the denominator. Often in such problems, we want to multiply the numerator and denominator by the conjugate of the denominator, which will usually eliminate the imaginary term from the denominator.

In this problem, the denominator is . Remember that, in general, the conjugate of the complex number is equal to , where a and b are both nonzero constants. Thus, the conjugate of is equal to .

We need to multiply both the numerator and denominator of the fraction by .

Next, we use the FOIL method to simplify both the numerator and denominator. The FOIL method of binomial multiplication requires us to mutiply together the first, outside, inner, and last terms of each binomial and then sum them.

Now, we can start simplifying.

Use the fact that .

The answer is .

Begin by factoring the radical expression using imaginary numbers:

Now, multiply the factors:

Simplify. Remember that is equivalent to

Begin by completing the square:

Now, multiply the factors. Remember that is equivalent to

Solve the equation using complex numbers:

Begin by factoring the radical expression using imaginary numbers:

Now, multiply the factors:

Simplify. Remember that is equivalent to

Begin by simplifying the radicals using complex numbers:

Multiply the factors:

Simplify. Remember that is equivalent to .

Begin by completing the square:

Multiply the factors:

Simplify. Remember that is equivalent to .

Begin by completing the square:

Now, multiply the factors:

Simplify. Remember that is equivalent to .

Use the FOIL (First, Outer, Inner, Last) to multiply the complex numbers:

Combine like terms and simplify. Remember that is equivalent to .

Use the FOIL (First, Outer, Inner, Last) method to expand the expression:

Simplify. Remember that is equivalent to .

Begin by multiplying the numerator and denominator by the conjugate of the denominator:

Combine like terms:

Simplify. Remember that is equivalent to .

Begin by multiplying the numerator and denominator by the conjugate of the denominator:

Combine like terms:

Simplify. Remember that is equivalent to .

Begin by simplifying the equation. Divide both sides by and take the square root.

Begin by simplifying the equation. Divide both sides by and take the square root.

Simplifying expressions with complex numbers uses exactly the same process as simplifying expressings with one variable. In this case, behaves similarly to any other variable. Thus, we have:

Multiplying top and bottom by the complex conjugate eliminates i from the denominator

Use FOIL to multiply. We can treat as a variable for now, just as if it were an .

Combine like terms.

Now we can substitute for .

Simplify.