Let us multiply the denominator and numerator with a rationalizing factor. So that we can simplify the denominator.
We know that sec² θ - tan² θ = 1
or, (sec θ - tanθ) (sec θ + tan θ) = 1, as A² - B² = (A-B) (A+B)
similarly we need to use: Cosec² Ф - Cot² Ф = 1
Sin² Ф + Cos ²Ф = 1 while rationalizing fractions.
if you are comfortable with Sin Ф and Cos Ф, then: