added classes

Console.java

@@ -14,6 +14,9 @@ public class Console {
     public static void println(String output, Object... args) {
         print(output + "\n", args);
     }
+    public static void printResult(Double result) {
+        System.out.println(result);
+    }
 
     public static String getStringInput(String prompt) {
         Scanner scanner = new Scanner(System.in);

Operations.java

@@ -55,16 +55,39 @@ public class Operations
                 result  = ScientificFunctions.sine(firstNumber);
                 //firstNumber = result;
                 //result = firstNumber;
+                Console.printResult(result);
             }
             if (command.equalsIgnoreCase("cos"))  {
                 // read first number
                 firstNumber = input.nextDouble();
-                // call the square method on calc and display
+                // call the cosine method on calc and display
                 result  = ScientificFunctions.cos(firstNumber);
+                Console.printResult(result);
             }
-            //if (command.equalsIgnoreCase("hex"))  {
+            if (command.equalsIgnoreCase("tan"))  {
             // call the square method on calc and display
-            //}
+                firstNumber = input.nextDouble();
+                result = ScientificFunctions.tangent(firstNumber);
+                Console.printResult(result);
+            }
+            if (command.equalsIgnoreCase("cos-1"))  {
+            // call the square method on calc and display
+                firstNumber = input.nextDouble();
+                result = ScientificFunctions.inverseCosine(firstNumber);
+                Console.printResult(result);
+            }
+            if (command.equalsIgnoreCase("sin-1"))  {
+            // call the square method on calc and display
+                firstNumber = input.nextDouble();
+                result = ScientificFunctions.inverseSine(firstNumber);
+                Console.printResult(result);
+            }
+            if (command.equalsIgnoreCase("tan-1"))  {
+            // call the square method on calc and display
+                firstNumber = input.nextDouble();
+                result = ScientificFunctions.inverseTangent(firstNumber);
+                Console.printResult(result);
+            }
             firstNumber = result;
             // and on and on
         }