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If-the-points-1-2i-and-1-4i-are-reflections-of-each-other-in-the-line-z-1-i-z-1-i-K-0-then-the-value-of-K-is-




Question Number 140444 by EnterUsername last updated on 07/May/21
If the points 1+2i and −1+4i are reflections of  each other in the line z(1+i)+z^� (1−i)+K=0, then  the value of K is _____.
$$\mathrm{If}\:\mathrm{the}\:\mathrm{points}\:\mathrm{1}+\mathrm{2}{i}\:\mathrm{and}\:−\mathrm{1}+\mathrm{4}{i}\:\mathrm{are}\:\mathrm{reflections}\:\mathrm{of} \\ $$$$\mathrm{each}\:\mathrm{other}\:\mathrm{in}\:\mathrm{the}\:\mathrm{line}\:{z}\left(\mathrm{1}+{i}\right)+\bar {{z}}\left(\mathrm{1}−{i}\right)+{K}=\mathrm{0},\:\mathrm{then} \\ $$$$\mathrm{the}\:\mathrm{value}\:\mathrm{of}\:{K}\:\mathrm{is}\:\_\_\_\_\_. \\ $$
Answered by mr W last updated on 08/May/21
midpoint from 1+2i and −1+4i is 3i,  which lies on the line.  z=3i, z^� =−3i  3i(1+i)−3i(1−i)+k=0  3i−3−3i−3+k=0  ⇒k=6
$${midpoint}\:{from}\:\mathrm{1}+\mathrm{2}{i}\:{and}\:−\mathrm{1}+\mathrm{4}{i}\:{is}\:\mathrm{3}{i}, \\ $$$${which}\:{lies}\:{on}\:{the}\:{line}. \\ $$$${z}=\mathrm{3}{i},\:\bar {{z}}=−\mathrm{3}{i} \\ $$$$\mathrm{3}{i}\left(\mathrm{1}+{i}\right)−\mathrm{3}{i}\left(\mathrm{1}−{i}\right)+{k}=\mathrm{0} \\ $$$$\mathrm{3}{i}−\mathrm{3}−\mathrm{3}{i}−\mathrm{3}+{k}=\mathrm{0} \\ $$$$\Rightarrow{k}=\mathrm{6} \\ $$
Commented by EnterUsername last updated on 12/May/21
Thanks
$$\mathrm{Thanks} \\ $$

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