A+B+C=180
B+C=180-A
sin(B+C)=sin(180-A)=sinA (As,sin(180- θ)=sin θ)
So,sin(B+C) = sinA
Question : If $\cos A = \sin ^2A$, and $a \sin ^{12}A+b \sin ^{10}A+c \sin ^{8}A+ \sin ^{6}A=1$, then $a + b + c$?
Option 1: 7
Option 2: 8
Option 3: 9
Option 4: 6
Question : If $\cos A + \cos B + \cos C = 3$, then what is the value of $\sin A + \sin B + \sin C$?
Option 1: $1$
Option 2: $2$
Option 3: $0$
Option 4: $-1$
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