49 Test file number 82

  49.1 Problem number 55
  49.2 Problem number 141
  49.3 Problem number 151
  49.4 Problem number 162
  49.5 Problem number 271
  49.6 Problem number 272
  49.7 Problem number 275
  49.8 Problem number 276

Test folder name:

test_cases/4_Trig_functions/4.2_Cosine/82_4.2.0-a_cos-^m-b_trg-^n