ATAR Notes: Forum
VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Specialist Mathematics => Topic started by: Teen on September 30, 2012, 10:29:44 pm
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what is effect of multiplying any complex number by i?
can someone use a diagram explain it.
thanks in advance:)
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It rotates the number 90 degrees anticlockwise about the origin.
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how?
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i(x+yi) = ix - y = -y + ix
i.e. rotation of 90 degrees counterclockwise
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i(x+yi) = ix - y = -y + ix
i.e. rotation of 90 degrees counterclockwise
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i understand the expanding ....how did u know from expansion, it rotates 90 degrees anticlockwise
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because x -> -y and y -> x, that's a counterclockwise rotation.
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alternatively, use polar numbers to understand it
i = cis( pi/2)
z*i = r*1cis(theta + pi/2), which you can see is a rotation anticlockwise of 90 degrees (pi/2)
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i(x+yi) = ix - y = -y + ix
i.e. rotation of 90 degrees counterclockwise
'
i understand the expanding ....how did u know from expansion, it rotates 90 degrees anticlockwise
draw it out.
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alternatively, use polar numbers to understand it
i = cis( pi/2)
z*i = r*1cis(theta + pi/2), which you can see is a rotation anticlockwise of 90 degrees (pi/2)
polar form way is easier to understand.....
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thanks everyone for ur help:)
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alternatively, use polar numbers to understand it
i = cis( pi/2)
z*i = r*1cis(theta + pi/2), which you can see is a rotation anticlockwise of 90 degrees (pi/2)
polar form way is easier to understand.....
You should have gone to Derrick Ha's spesh lecture. He explained about it in this way