Find the sum of real values of x and y for which the following equation is satisfied:
3 + i ( 1 + i ) x − 2 i + 3 − i ( 2 − 3 i ) y + i = i .
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L H S = 3 + i ( 1 + i ) x − 2 i + 3 − i ( 2 − 3 i ) y + i
= 1 0 [ ( 1 + i ) x − 2 i ] ( 3 − i ) + 1 0 [ ( 2 − 3 i ) y + i ] ( 3 − i )
= 5 2 x + 5 i x − 5 1 − 5 3 i + 1 0 3 i − 1 0 7 y i + 1 0 9 y − 1 0 1
= i ( 5 x − 1 0 7 y − 1 0 3 ) + ( 5 2 x + 1 0 9 y − 1 0 3 ) = 1 i + 0
As two complex numbers are equal if and only if their real parts are equal and their imaginary parts are also equal, we have:
⎩ ⎪ ⎨ ⎪ ⎧ 5 x − 1 0 7 y − 1 0 3 = 1 5 2 x + 1 0 9 y − 1 0 3 = 0
⇔ { x = 3 y = − 1
Hence, the sum of real values of x , y is 2
@ Tín Phạm Nguyễn Nice solution for a really overrated problem
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I can't imagine this problem being worth 400 points!
Is there a better solution other than putting x=a+ib and so for y...
see my above solution.. hope you will like it :D
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