sin(x) + cos(x) = a | sin(x) - cos(x) = ???

Question

given sin(x) + cos(x) = a

sin(x) - cos(x) = ???

 

A. 1
B. Sqrt (1-a^2)
C. 2 - a^2
D. Sqrt (2-a^2)
E. 1-a^2

Answer 1

sin x + cos x = a

sin x = a - cos x

 

sin x - cos x = a - cos x - cos x

sin x - cos x = a - 2cos x