Funciones trigonométricas preguntas y respuestas anteriores
Solución: sen (π/4-α) = sen (π/2-π/4-α).
=sin[π/2-(π/4+α)].
=cos(π/4+α).
=√[1-sin^2(π/4+α)].
=-2√2/3(∵α& gt;π/2∴cos(π /4+α)<0.)
=sin[π/2-(π/4+α)].
=cos(π/4+α).
=√[1-sin^2(π/4+α)].
=-2√2/3(∵α& gt;π/2∴cos(π /4+α)<0.)