Question

How do I simplify this complex root

Answer 1

Very rusty on my complex numbers knowledge

Answer 2

just divvy up the sqrt part into sqrt(-1) and sqrt(40)

leave the sqrt(-1) alone and work out the rest as usual

Answer 3

Divide everything by 8?

Answer 4

So -0.5+/- 5i?

Answer 5

sqrt(-40) = sqrt(40) sqrt(-1)

Answer 6

then yes, factor out commons and simplify to your hearts content

Answer 7

2sqrt(10)/8 not= 5

Answer 8

@amistre64 So you have it like this??

Answer 9

yes, to start with

Answer 10

sqrt(-1) = i so just ignore it in the rest of the usual simplificating

Answer 11

\[\frac{-4\pm\sqrt{40}\ i}{8}\]

Answer 12

I see, I can simplify the root 40 even further, trying to keep to nice round numbers rather than decimals.

Answer 13

correct

Answer 14

4root10

Answer 15

\[\frac{-4\pm\sqrt{40}\ i}{8}\]
\[\frac{-4\pm\sqrt{4}\sqrt{10}\ i}{8}\]
\[\frac{-4\pm2\sqrt{10}\ i}{8}\]
\[\frac{2(-2\pm\sqrt{10}\ i)}{8}\]

Answer 16

Works out nicely.

@amistre64 I am having problems rest of the question. I have complex roots now