4. (06.05, 06.06 HC) Students were asked to prove the identity (cot x)(cos x)=cscx- sin x. Two students' work is given. Student A Student B Step 1: COSXx sinx cosxCicx sinx Step 1: cotx cos x= sinx sinx Step 2: cos x esex - sinx sinx Step 2: cotx cos x sinxsinx Step 3: 1-sin2, seex sinx Step 3: cot x cos x sinx 1-sin2x sinx Step 4: cscx-sinx Step 4: cosx cotx cos x sinx sinx sinx Step 5: cscx - sin x cscx-sinx Step 5: cotx cos x COS X COSX sinx Step 6: cot x cos xcot x cos x Part A: Did either student verify the identity properly? Explain why or why not. (10 points) two entities that were used in Student A's verification and the steps they appear in. (5 points)