Question

Write the expression in standard form

Answer 1

\[\frac{ 2 }{ 2-15i }\]

Answer 2

I multiplied both the top and bottom by the denominators conjugate but got 4+30i/4+225i^2

Answer 3

@study100

Answer 4

multiply top and bottom by (2+15i)

Answer 5

I did, and I got 4+30i/4+225i^2

Answer 6

i²=-1

Answer 7

z.z*=|z|², then it can't be negative

Answer 8

what raphael said :)

Answer 9

what is the modulus of a+bi?

Answer 10

Wait, well I know i^2 is -1, but 4-225 equals -221, not -229 like my answer choices

Answer 11

Modulus? Do you mean conjugate?

Answer 12

no

Answer 13

You made a minor sign mistake
4+30i / 2=4 - 225i^2

Answer 14

remember
(ax+b)(ax-b)= (ax)^2 - b^2

Answer 15

what is the modulus of that number , the size of vector?

Answer 16

isn't it a²+b²?

Answer 17

4+30i/4+225

Answer 18

(x+2)(x-2) = (x^2 + 2x-2x -4) = x^2 -4

Answer 19

then z.z*=[sqrt(15²+2²)]²=225+4

Answer 20

for example, that problem

Answer 21

so the answer would be

Answer 22

\[\frac{ 4 }{ 229 }+\frac{ 30 }{ 229 }i\]

Answer 23

Yes :)

Answer 24

Thank you both! :)

Answer 25

You're welcomed :)

Answer 26

you are welcome