What is tan4?

Can someone verify that sec4 theta-sec2 theta equals tan4 theta plus tan2 theta?

sec4(Θ) - sec2(Θ) = tan4(Θ) + tan2(Θ)Factor each side: sec2(Θ) [sec2(Θ) - 1] = tan2(Θ) [tan2(Θ) + 1]Use the identitiy: 1 + tan2(Θ) = sec2(Θ)We can also write it as: tan2(Θ) = sec2(Θ) - 1Substitute the first form of the identity in the right side: sec2(Θ) [sec2(Θ) - 1] = tan2(Θ) sec2(Θ)Substitute the second form of the identity in the left side: sec2(Θ) tan2(Θ) = tan2(Θ) sec2(Θ)Is that close enough for you ?Is it worth a trust point ?