# Pre Calculus

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Pre Calculus

why is sin(-20)/cos 380

equal to tan (-200)

• Pre Calculus -

I covered this previously.

Sin(theta)=sin(theta+360) in degrees
Sin(-theta)=sin(Theta) in degrees

sin(-20)=-sin(20) =-sin(20+360)=-sin(380)
then...
Tan(-theta)=-tan(theta).

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