Respuesta :
Hello from MrBillDoesMath!
Answer:
-2/5
Discussion:
Generally,
tan(2*PI - x ) = - tanx => (*)
and in our case
tan(2*PI - x ) = - tanx = - (2/5) = -2/5
Proof of (*)
tan (2*PI-x) = sin (2*Pi-x)/ cos(2*Pi-x)
Now
sin(2*Pi) * cos(-x) - cos(2*Pi) sin(x) => ( sin(2*PI) = 0, cos(2*Pi) = 1)
= -sin(x)
cos(2*Pi-x) = cos(2*Pi) * cos(-x) + sin(2*Pi)* sin(-x) =>
1 * cos(-x) + 0 =
1 * cos(x) = cos(x)
so tan (2*PI-x) = (-sin(x)) / cos(x) = -tanx
Regards,
MrB
