Check: (tanx + cotx)^2= seg^2x + csc^2x —>
(1) LHS = (tanx + cotx)^2 = [(sin^2x + cos^2x)/(sinx cosx)]^2
(2) LHS = (sinx cosx)^-2
(3) RHS = sec^2x + csc^2x = (1/cos^2 + 1/sin^2)^2
(4) RHS = (sin^2x + cos^2x)/(cos^2x sin^2x) = 1/(cosx sinx)^2
(5) RHS = (cosx sinx)^-2
(6) LHS = HRH