if sinA+SinB+sinC=3

find the value of cosA+cosb+cosC???

• Since the maximum value for sin is 1 and since you have three sin's adding up to 3, each of the sin's must be 1! (If any of the sin's are not 1, then there is no way for the other two to make up the difference.) So A = B = C = 90 degrees or any angle coterminal with 90 degrees. And the cos of 90 degrees is zero. So cos(A)+cos(B)+cos(C) = 0+0+0 = 0.
• 11 years agoHelpfull: Yes(2) No(0)