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.

One of the biggest drivers for digital identity is to be able to verify who you are and that what you’re saying is real amid the extreme (and somewhat scary) growth of artificial intelligence ...