What does $cos(arctan(sin((-3pi)/4)) )$ equal?

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Answer 1 · 2016-03-17T15:37:00

$sqrt(1/2)$

Operations are from innermost parantheses in the nest.
$sin(-3pi/4)=- sin(pi-pi/4)=-sin(pi/4)=-1/sqrt2$

$arctan(-1/sqrt2)=-arctan(1/sqrt2)=-pi/4$

$cos(-pi/4) = cos(pi/4) = 1/sqrt2$ .

What does cos(arctan(sin((-3pi)/4)) )cos(arctan(sin((-3pi)/4)) ) equal?