Finding polar and cartesian form for this power

In summary, to find the polar and cartesian form of ((-1+i)/(√2))^1002, you must first find the absolute value and argument of the original equation. Then, raise it to the power of 1002 and simplify to get the angle in terms of a principal argument. Finally, take the cosine and sine of the angle and multiply them by the absolute value to get the polar form. To get the cartesian form, multiply the absolute value by the cosine and add the absolute value times the sine times i.
  • #1
charmedbeauty
271
0

Homework Statement



((-1+i)/(√2))^1002
find polar and cartesian form

Homework Equations





The Attempt at a Solution




So I started by finding |z|=1

and Arg(z)= arctan (-1) = 5pi/6

so 1^(1002)*e^(i*5pi/6)*1002 =1*e^(i*835pi)

but that's as far as I got because the answer says -i, but to get that term I need 1*e^-ipi/2

any thoughts??
 
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  • #2
Your main problem is that [itex]arctan(-1)[/itex] is NOT [itex]5\pi/6[/itex]!

Calculate that again.
 
  • #3
HallsofIvy said:
Your main problem is that [itex]arctan(-1)[/itex] is NOT [itex]5\pi/6[/itex]!

Calculate that again.

I was assuming since the original eqn has a negative real part then I would add Pi/2 since the angle is measured from 0.
Although I am getting 3pi/4 now
 
  • #4
Well, yes (3pi)/4 is the angle you're looking for since this is in the second quadrant.

You have got |z|, and now you have the angle.

Put it into exponential form to the power of 1002, and simplify it to get the angle in terms of a principal argument.
 
  • #5
NewtonianAlch said:
Well, yes (3pi)/4 is the angle you're looking for since this is in the second quadrant.

You have got |z|, and now you have the angle.

Put it into exponential form to the power of 1002, and simplify it to get the angle in terms of a principal argument.

Ok so now I have 1^1002*(cos 3Pi/4+isin3Pi/4)

= 1*(0)=0 how do they get the minus i?
 
  • #6
charmedbeauty said:
Ok so now I have 1^1002*(cos 3Pi/4+isin3Pi/4)

= 1*(0)=0 how do they get the minus i?

How did you get 0 for (cos 3Pi/4 + isin 3Pi/4) ?

Also, you have forgotten to raise that to the power.
 
  • #7
NewtonianAlch said:
How did you get 0 for (cos 3Pi/4 + isin 3Pi/4) ?

Also, you have forgotten to raise that to the power.

isnt cos 3pi/4=-0.7...

and sin 3pi/4=0.7...
 
  • #8
charmedbeauty said:
isnt cos 3pi/4=-0.7...

and sin 3pi/4=0.7...

Yes, but you have a complex number there.

-0.707 +0.707i

You can't add them just like that.

What of the 1002? You need to account for that too.
 

Related to Finding polar and cartesian form for this power

1) What is the difference between polar and cartesian form?

Polar and cartesian forms are two ways of representing complex numbers. In polar form, a complex number is expressed in terms of its magnitude (or absolute value) and angle, while in cartesian form, it is expressed in terms of its real and imaginary parts.

2) How do you convert a complex number from cartesian to polar form?

To convert a complex number from cartesian to polar form, you can use the following formula: r = √(a^2 + b^2) and θ = tan^-1(b/a), where a is the real part and b is the imaginary part of the complex number.

3) How do you convert a complex number from polar to cartesian form?

To convert a complex number from polar to cartesian form, you can use the following formula: a = r cos(θ) and b = r sin(θ), where r is the magnitude and θ is the angle of the complex number.

4) Can a complex number have more than one polar form?

Yes, a complex number can have an infinite number of polar forms, since the angle (θ) can be expressed in multiple ways (e.g. in degrees or radians).

5) Why are polar and cartesian forms important in science?

Polar and cartesian forms are important in science because they allow us to easily perform mathematical operations on complex numbers, which are often used to represent physical quantities in fields such as physics, engineering, and mathematics.

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