Esay Complex Number Question (1 Viewer)

[CLD]

Hi all,

How do you sketch Im(z) = |z|?

I think it is a circle?

 

[nightweaver066]

When in doubt, let z = x + iy

Let z = x + iy











However |x^2 + y^2| 0, so the solution is the positive imaginary axis, i.e.

 

[jnney]

y = sqrt(x^2+y^2)

y^2=x^2+y^2

x^2=0

x=0

 

[jnney]

damn you nightweaver.

 

[seanieg89]

When in doubt, let z = x + iy

Let z = x + iy

You are adding false solutions when you square both sides, the answer is just the non-negative half of the imaginary axis.

 

[nightweaver066]

damn you nightweaver.

<3

 

[nightweaver066]

You are adding false solutions when you square both sides, the answer is just the non-negative half of the imaginary axis.

Ahh yeah that makes sense. Should be more careful..

 

[CLD]

So, wait, what is the answer then?

 

[jnney]

So, wait, what is the answer then?

the top half of the y-axis.

 

[CLD]

the top half of the y-axis.

So x=0??? but seaning said it is wrong?

 

[zeebobDD]

its so easy you can't spell easy:L

 

[jnney]

So x=0??? but seaning said it is wrong?

sean is right. the x=0 IS the y=axis.

 

[Carrotsticks]

the top half of the y-axis.

So x=0??? but seaning said it is wrong?

 

[SpiralFlex]

"Beware the twraps of modulus" quoted from my side-kick.

 

[CLD]

Okay but how can you sketch x=0 and y>(equal to)0 on one graph paper?

 

[jnney]

Okay but how can you sketch x=0 and y>(equal to)0 on one graph paper?

it's just a single line on the y=axis. Except:

y>=0 is a condition which the graph x=0 must satisfy. it means that this particular graph does not extend below the origin.

 

[Carrotsticks]

Okay but how can you sketch x=0 and y>(equal to)0 on one graph paper?

x=0 implies the entire Y axis.

y greater than or equal to zero implies the top half of the xy plane (ie: Quadrants 1 and 2).

The only region satisfying both these conditions is the top half of the Y axis (including the origin).

 

[umm what]

http://community.boredofstudies.org/showthread.php?t=280133

SOMEONE DO THIS -.- plzzzz

 

[umm what]

http://community.boredofstudies.org/showthread.php?t=280133 can u do this plzzz

x=0 implies the entire Y axis.

y greater than or equal to zero implies the top half of the xy plane (ie: Quadrants 1 and 2).

The only region satisfying both these conditions is the top half of the Y axis (including the origin).

 

[school4nerds]

let z= x+iy,

Im(z)= y

|z|= (sqrt)(x^2 + y^2)

y^2= x^2+y^2

x^2=0

x=0

why is this wrong? i thought you could square both sides? :\