If interpreted as shown, the order is shown in the lines following 1+sin(x)/1-sin(x)-1-sin(x)/1+sin(x) =1 + ((sin(x))/1) - sin(x) -1 - (sin(x)/1) + sin(x) which is completely meaningless for the purpose of this question.
The left-hand side is common denominator is (1-sin(x))(1+sin(x)), so using a^2-b^2=(a+b)(a-b) <span>