# AS Further maths: argand diagrams and arguments

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Most of the bloody questions for hw i get states that I have to answer my questions in terms of pi & I don't know pi's significance to the argand diagram!!! Can someone please explain?? :ccc

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#2

Do you have an example of a question? Pi alone would just be a real component, whereas Pi(i) is an imaginary component

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#3

(Original post by

Most of the bloody questions for hw i get states that I have to answer my questions in terms of pi & I don't know pi's significance to the argand diagram!!! Can someone please explain?? :ccc

**SufferinStudent**)Most of the bloody questions for hw i get states that I have to answer my questions in terms of pi & I don't know pi's significance to the argand diagram!!! Can someone please explain?? :ccc

Have you covered how to calculate the argument of a complex number?

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(Original post by

Do you have an example of a question? Pi alone would just be a real component, whereas Pi(i) is an imaginary component

**PuffyPenguin**)Do you have an example of a question? Pi alone would just be a real component, whereas Pi(i) is an imaginary component

write in form a+bi-

4(cos(-5pi /6) + isin(-5pi /6)

How would you do this?

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(Original post by

Have you covered radians at all in maths? A decent chunk of maths at A Level works in radians rather than degrees, which is where the pi stuff comes from.

Have you covered how to calculate the argument of a complex number?

**an_atheist**)Have you covered radians at all in maths? A decent chunk of maths at A Level works in radians rather than degrees, which is where the pi stuff comes from.

Have you covered how to calculate the argument of a complex number?

but idk about the radians stuff , do you know where the pi stuff comes from?

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yeah I know how to calculate the argument which is tan= y/x right?

but idk about the radians stuff , do you know where the pi stuff comes from?

**SufferinStudent**)yeah I know how to calculate the argument which is tan= y/x right?

but idk about the radians stuff , do you know where the pi stuff comes from?

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#7

You can write the sin and cos parts as real numbers, i.e. Cos(-5pi/6) is - root3/2 and sin(-5pi/6) is -1/2. If you sub that in you get -2root 3 -1/2 i

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#9

The angle between that vector and the positive x-axis is defined as the argument. Going anticlockwise (positive y quadrants) goes from 0to pi and going clockwise (negative y quadrants) goes from 0 to -pi.

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#10

**SufferinStudent**)

yeah I know how to calculate the argument which is tan= y/x right?

but idk about the radians stuff , do you know where the pi stuff comes from?

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#11

(Original post by

using radians is 'neater' for the purposes of doing maths (as I understand it)

**an_atheist**)using radians is 'neater' for the purposes of doing maths (as I understand it)

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The angle between that vector and the positive x-axis is defined as the argument. Going anticlockwise (positive y quadrants) goes from 0to pi and going clockwise (negative y quadrants) goes from 0 to -pi.

**black1blade**)The angle between that vector and the positive x-axis is defined as the argument. Going anticlockwise (positive y quadrants) goes from 0to pi and going clockwise (negative y quadrants) goes from 0 to -pi.

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(Original post by

You can write the sin and cos parts as real numbers, i.e. Cos(-5pi/6) is - root3/2 and sin(-5pi/6) is -1/2. If you sub that in you get -2root 3 -1/2 i

**PuffyPenguin**)You can write the sin and cos parts as real numbers, i.e. Cos(-5pi/6) is - root3/2 and sin(-5pi/6) is -1/2. If you sub that in you get -2root 3 -1/2 i

**SufferinStudent**)

Most of the bloody questions for hw i get states that I have to answer my questions in terms of pi & I don't know pi's significance to the argand diagram!!! Can someone please explain?? :ccc

You can then use a right angled triangle to work out the angle

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#14

(Original post by

so could you treat pi as 180 degrees? are they equivalent?

**SufferinStudent**)so could you treat pi as 180 degrees? are they equivalent?

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See comment above

You can then use a right angled triangle to work out the angle

**PuffyPenguin**)See comment above

You can then use a right angled triangle to work out the angle

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(Original post by

They represent the same thing yes but in pure maths we use radians because they are more useful as pi is an irrational number that is defined in a few ways but it's directly intertwined with how circles work. You'll have to get used to radians sooner or later although I can see why you might be confused because you normally go over radians first in core 2.

**black1blade**)They represent the same thing yes but in pure maths we use radians because they are more useful as pi is an irrational number that is defined in a few ways but it's directly intertwined with how circles work. You'll have to get used to radians sooner or later although I can see why you might be confused because you normally go over radians first in core 2.

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