Bob is verifying the identity, sin 3x + x) = - cos x. He took these steps: Step 1: sin (31 + x)=sin3A. cosx -cos Tinx
no .
Step 2: = sin
COS X + 0
Step 3: = -1.cos x + 0
He made a mistake at which step? Step

What is the next step in the given proof? choose the most logical approach. a. statement: m 1 + m 2 + 2(m 3) = 180° reason: angle addition b. statement: m 1 + m 3 = m 2 + m 3 reason: transitive property of equality c. statement: m 1 = m 2 reason: subtraction property of equality d. statement: m 1 + m 2 = m 2 + m 3 reason: substitution property of equality e. statement: 2(m 1) = m 2 + m 3 reason: substitution property of equality