Prove an identity by rationalizing the denominator Posted: March 30, 2026 | Last updated: March 30, 2026 👉 Learn how to verify rational trigonometric identities involving the addition and subtraction ...

There are some trigonometric identities which you must remember in order to simplify trigonometric expressions when required. When you are asked to prove something, ignore the right hand side of the ...

Sec(a-b) = cos(a+b) / cos^2a - sin^2b I'm trying to prove this, by turning the left side into the right. I am stuck. Presumably you have already done the sum and difference formulas for sin and cos.

Stephen has degrees in science (Physics major) and arts (English Literature and the History and Philosophy of Science), as well as a Graduate Diploma in Science Communication. Stephen has degrees in ...