Question

If sin A1+ sin A2+ sinA3 =3 find cosA1+cos A2+ cosA3

Answer 1

If sina1+sina2+sina3=3, and max. Value of sin theta =1=sin 90
So,sina1=sina2=sina3=sin90°
So,a1=a2=a3=90
So,cosa1+cosa2+cos a3=cos90+cos90+cos90=0.
Hence,cosa1+cosa2+cosa3=0
Hope it helps

Answer 2

hey there,

sina1 + sina2 + sina3 = 3
we know ,
sine maximum value= 1
so, above expression is correct only when , sina1 = sina2 = sina3 = 1
e.g a1 = a2 = a3 = 90°

but we know ,
cos90° = 0
so, cosa1 = cosa2 = cosa3 = 0

hence,
cosa1 + cosa2 + cosa3 = 0 

Hope this helps!