39 Test file number 67

  39.1 Problem number 50
  39.2 Problem number 51
  39.3 Problem number 52
  39.4 Problem number 53
  39.5 Problem number 54
  39.6 Problem number 55
  39.7 Problem number 56
  39.8 Problem number 57

Test folder name:

test_cases/4_Trig_functions/4.1_Sine/67_4.1.1.1-a+b_sin-^n