How do you evaluate sine, cosine, tangent of $-405^circ$ without using a calculator?

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Answer 1 · 2018-02-20T09:06:22

$sin(-405) = -(1/sqrt2)$

$cos(-405) = (1/sqrt2)$

$tan(-405) = -1$

$sin (-405) = sin (-360 - 45) = sin (-45) = - sin 45= -(1/sqrt2)$

$cos (-405) = cos (-360 - 45) = cos (-45) = cos 45= (1/sqrt2)$

$tan (-405) = tan (-360 - 45) = tan (-45) = - tan 45= -1$

How do you evaluate sine, cosine, tangent of -405^circ-405^circ without using a calculator?