How do you find exact value with out calculator $1-tan^2 10+ csc^2 80$ ?

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Answer 1 · 2015-02-08T12:56:25

Try this method

$t = 1-tan^2(10^0)+csc^2(80^0)$
$= 1-tan^2(10^0)+csc(90^0-10^0)^2$
$=1-tan^2(10^0)+sec^2(10^0)$
$=1+(1-sin^2(10^0))/cos^2(10^0)$
$=1+1$
$=2$

How do you find exact value with out calculator 1-tan^2 10+ csc^2 801-tan^2 10+ csc^2 80?