Mathematics

# If $A,B$ are complementary angles, then $\cos ^{ 2 }{ A } +\cos ^{ 2 }{ B }$

##### SOLUTION
$co{s^2}A + co{s^2}B$
And $A$ and $B$ are complementary
So
$A+B=90,A=90-B$
${\left( {cos\left( {90 - B} \right)} \right)^2} + co{s^2}B$
$= {\sin ^2}B + {\cos ^2}B = 1$

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Subjective Medium Published on 09th 09, 2020
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