We will assume that 120 and 150 are the arguments of functions. Suppose that by default between the functions and the number 12, the sign is omitted [*].
Then the value of sin150 = 0.5 is determined to solve;COS120 = -0.5.
Having shifting 12*0.5*(-0.5) =-3.
If the recording is correctly deciphered, it should be.
In this particular case, you can use the formula for the transforming work of the sinus and cosine in the sum of sinuses and formulas determining the trigonometric functions of the angles when turning 180 degrees.
