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# Confusion with finding the mod-argument for of just '7 + 0i' watch

1. Hi, i would have thought the modulus-argument form of 7 would = 7(cos0 + isin0), which would give the right answer but i look in the answer section of my FP2 book and i'm seeing that they have 7 = 7(cosθ + isinθ), maybe a mistake by the authors thinking they were zeros but just want to make sure i'm not missing anything here.
2. I've found the question - I agree with you. Modulus-argument form requires that you give a value for both r and θ.
3. (Original post by Dylex)
Hi, i would have thought the modulus-argument form of 7 would = 7(cos0 + isin0), which would give the right answer but i look in the answer section of my FP2 book and i'm seeing that they have 7 = 7(cosθ + isinθ), maybe a mistake by the authors thinking they were zeros but just want to make sure i'm not missing anything here.
My answer to this question would be neither. It'd be 7 = 7(cos(n*2pi)+isin(n*pi))
where n is a natural number (0,1,2,3,...)
4. Definitely true - in this instance though answers were required to be in the form .

Attwood, G. and Pledger, K. (2009) Edexcel AS and A Level Modular Mathematics Further Pure Mathematics 2. Harlow: Edexcel.
pg. 23 ex. 3A qu. 1a
5. (Original post by 45.46 Litre Hat)
Definitely true - in this instance though answers were required to be in the form .

Attwood, G. and Pledger, K. (2009) Edexcel AS and A Level Modular Mathematics Further Pure Mathematics 2. Harlow: Edexcel.
pg. 23 ex. 3A qu. 1a
Theta is inferior or equal to pi. sin is 0 both at theta = 0 and theta = pi.
6. (Original post by candyaljamila)
Theta is inferior or equal to pi. sin is 0 both at theta = 0 and theta = pi.
Ah I missed that, thanks.

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