Question #2b052

Question

Question #2b052

1 Answer

Impact of this question

939 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2017-10-18T22:42:01

The answer is 5.

Explanation:

This is an example of two factors that are complex conjugates . The two binomials have the same real and imaginary parts, but one is a sum while the other is a difference of terms.

The result is always a real number.

(It's similar to $(x + 2) (x - 2) = x^{2} - 2^{2}$ $(x+2)(x-2) = x^2 - 2^2$ )

Use the FOIL method as you would for any other binomial:

$2 \cdot 2 + 2 \cdot i - 2 \cdot i - i^{2}$ $2*2 + 2*i - 2*i -i^2$

The second and third term cancel, leaving

$4 - i^{2}$ $4-i^2$

Since $i^{2} = - 1$ $i^2=-1$ the value is $4 + 1 = 5$ $4+1=5$

Science

Math

Humanities

... and beyond

Question #2b052

1 Answer

Explanation:

Related questions

Impact of this question