Simplify the expression sin(x) / cos(x) + cos(x) / sin(x).
Simplify the expression cos^2(x) - sin^2(x).
Solve the equation tan(x) = 1 for values of x in the interval [0, 2π).
: Determine the value of sin(θ) if cos(θ) = 3/5 and θ is in the second quadrant.
Simplify the expression sec(x) / tan(x) + cos(x) / sin(x).
Simplify the expression tan(x) + cot(x).