Complex Subtraction/Examples/(6 - 2i) - (2 - 5i)
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Example of Complex Subtraction
- $\paren {6 - 2 i} - \paren {2 - 5 i} = 4 + 3 i$
Proof 1
\(\ds \paren {6 - 2 i} - \paren {2 - 5 i}\) | \(=\) | \(\ds \paren {6 - 2} + \paren {-2 - \paren {-5} } i\) | Definition of Complex Subtraction | |||||||||||
\(\ds \) | \(=\) | \(\ds 4 + 3 i\) |
$\blacksquare$
Proof 2
By definition of complex subtraction:
- $\paren {6 - 2 i} - \paren {2 - 5 i} = \paren {6 - 2 i} + \paren {-2 + 5 i}$
Let the complex numbers $6 - 2 i$ and $-2 + 5 i$ be represented by the points $P_1$ and $P_2$ respectively in the complex plane.
Complete the parallelogram with $OP_1$ and $OP_2$ as the adjacent sides.
Using Geometrical Interpretation of Complex Addition, the point $P$ represents the complex number $4 + 3 i$, which is the sum of $6 - 2 i$ and $-2 + 5 i$.
Hence, $4 + 3 i$ is the difference of $6 - 2 i$ and $2 - 5 i$.
$\blacksquare$