I need help solving this questiong If cos(x)=-1/2 and ?/2<x<?, find : sin[x+?/4]
D Dmoney1578 New member Joined May 2, 2008 Messages 7 May 2, 2008 #1 I need help solving this questiong If cos(x)=-1/2 and ?/2<x<?, find : sin[x+?/4]
tkhunny Moderator Staff member Joined Apr 12, 2005 Messages 11,339 May 2, 2008 #2 You should have an expansion formula. Memorize it. sin(a+b) = sin(a)cos(b) + cos(a)sin(b) That's about all you need. Fir the future, you'll need the cosine version, too.
You should have an expansion formula. Memorize it. sin(a+b) = sin(a)cos(b) + cos(a)sin(b) That's about all you need. Fir the future, you'll need the cosine version, too.
