posted by tony .
simplify the expression.
Parentheses are assumed missing. Implied parentheses are ALWAYS required in numerator and denominator of fractions.
This problem can be solved by converting all functions in terms of sine and cosine according to the standard definitions.
Use sin²(u)+cos²(u)=1 to reduce the numerator to 1.
Since the denominator has a common factor of sin²(x), we can simplify that too!