mridrik
What is the modulus of 7  8i?



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mridrik
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How do you do this?

TAKEBACKMATH
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what is modulus?

mridrik
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hard to explain, at least for me it is

mathslover
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@mridrik Do you know how to find the modulus of the general form of complex numbers?

mridrik
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no

mridrik
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I know like 8 % 12 = 8
and stuff like that

mathslover
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OK no problem, let me give you an introduction to the modulus of complex numbers.

mathslover
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Let there be Z (a complex number ) = a + ib
So , we have to find the modulus of Z = Z = a+ib
It is given by Z = \(\sqrt{x^2+y^2}\)

mathslover
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oops sorry Z = \(\sqrt{a^2+b^2}\)

UnkleRhaukus
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dw:1350706728154:dw

mridrik
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so positive radical 113?

UnkleRhaukus
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dw:1350706781969:dw

mathslover
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so let us take the question itself as an example :
78i = \(\sqrt{7^2+8^2}\)= \(\sqrt{49 + 64} = \sqrt{113}\)

mathslover
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Good work @mridrik , you're right!

UnkleRhaukus
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right!

mridrik
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alright thanks, what were you drawing there unkle?

UnkleRhaukus
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i plotted the point 7  8i on an Argand diagram,
then used the Pythagorean relation to determine the distance form the origin of the point

UnkleRhaukus
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from*

UnkleRhaukus
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modulus is just the length of the vector

mridrik
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oh, okay