Question

tan²theta+tan⁴theta=sec⁴theta-sec²theta​

Answer 1

${tan}^{2} \theta + {tan}^{4} \theta \\ \\ = {tan}^{2} \theta(1 + {tan}^{2} \theta) \\ \\ = {tan}^{2} \theta {sec}^{2} \theta \\ \\ = ( {sec}^{2} \theta - 1) {sec}^{2} \theta \\ \\ = {sec}^{4} \theta - {sec}^{2} \theta$