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Prove that `|Z-Z_1|^2+|Z-Z_2|^2=a`will represent a real circle [with center `(|Z_1+Z_2|^//2+)`] on the Argand plane if `2ageq|Z_1-Z_1|^2` |
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Answer» `|z-z_(1)|^(2)+|z-z_(2)|^(2)=a` `implies(z-z_(1))(bar(z)-bar(z)_(1))+(z-z_(2))(bar(z)-bar(z)_(2))=a` `implies2zbar(z)-z(bar(z)_(1)+bar(z)_(2))-bar(z)(z_(1)+z_(2))+z_(1)bar(z)_(1)+z_(2)bar(z)_(2)=a` `implieszbar(z)=z((bar(z_(1))+bar(z_(2)))/(2))-bar(z)((z_(1)+z_(2))/(2))+(z_(1)bar(z)_(1)+z_(2)bar(z)_(2)-a)/(2)=0" "(1)` Above equation is of the form `zbar(z)+alphabar(z)+bar(alpha)z+beta=0`, which represents the real circle if `alphabar(alpha)-betage0` `implies((z_(1)+z_(2))(bar(z_(1))+bar(z_(2))))/(4)ge(z_(1)bar(z_(1))+z_(2)bar(z_(2))-a)/(2)` `implies2agez_(1)bar(z_(1))+z_(2)bar(z_(2))-z_(1)bar(z_(2))-z_(2)bar(z_(1))` `implies2age|z_(1)-z_(2)|^(2)` |
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