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| 1. |
Sec4x - sec2x = 2 |
| Answer» Sec[2x] = 1/(2Cos²(x) - 1) Sec[4x] = 1/(2((2Cos²(x) - 1)² - 1) Let z = Cos²(x) Then we have: 1/(2(2z - 1)² - 1) - 1/(2z - 1) = 2 which eventually reduces to the quadratic equation: 16z² - 20z + 5 = 0 with solutions z = (1/8)(5 ± √5) | |