How do I find the value of sec -3pi/4?

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Answer 1 · 2015-08-22T12:52:22

$sec((-3pi)/4) = -sqrt(2)$

$sec = ("hypothenuse")/("adjacent side")$
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Answer 2 · 2015-08-22T23:39:09

Find $sec ((-3pi)/4)$

Ans: $- sqrt2$

Another way to find $sec((-3pi)/4)$

$sec ((-3pi)/4) = 1/sin ((-3pi)/4).$ Find $sin ((-3pi)/4)$

On the trig unit circle,
$sin ((-3pi)/4) = sin (-pi/4) = - sin (pi/4) = - sqrt2/2$
Therefor:
$sec ((-3pi)/4) = (1/sin) = -2/sqrt2 = - sqrt2$