Difference between revisions of "2023 AMC 12B Problems/Problem 12"

(Problem)
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==Problem==
 
==Problem==
For complex number <math>u = a+bi and </math>v = c+di<math> (where </math>i=\sqrt{-1}<math>), define the binary operation
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For complex number <math>u = a+bi</math> and <math>v = c+di</math> (where <math>i=\sqrt{-1}</math>), define the binary operation
  
</math>u \earth v = ac \plus bdi<math>
+
<math>u \earth v = ac \plus bdi</math>
 
    
 
    
</math>\textbf{(A) }\frac{9}{25}\qquad\textbf{(B) }\frac{1}{9}\qquad\textbf{(C) }\frac{1}{5}\qquad\textbf{(D) }\frac{25}{169}\qquad\textbf{(E) }\frac{4}{25}$
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<math>\textbf{(A) }\frac{9}{25}\qquad\textbf{(B) }\frac{1}{9}\qquad\textbf{(C) }\frac{1}{5}\qquad\textbf{(D) }\frac{25}{169}\qquad\textbf{(E) }\frac{4}{25}</math>

Revision as of 17:34, 15 November 2023

Problem

For complex number $u = a+bi$ and $v = c+di$ (where $i=\sqrt{-1}$), define the binary operation

$u \earth v = ac \plus bdi$ (Error compiling LaTeX. Unknown error_msg)

$\textbf{(A) }\frac{9}{25}\qquad\textbf{(B) }\frac{1}{9}\qquad\textbf{(C) }\frac{1}{5}\qquad\textbf{(D) }\frac{25}{169}\qquad\textbf{(E) }\frac{4}{25}$