Question 815665
Please include instructions with your problem. What are you/we supposed to do with this equation? Please re-post your question with the instructions.<br>
P.S.<ul><li>If the problem is to solve for k or to prove the identity, then here are some steps to try:<ol><li>Factor the left side as a difference of squares.</li><li>Use the identity {{{tan^2(k) + 1 = sec^2(k)}}} to replace the tan^2's with {{{sec^2(k)-1}}}</li></ol></li><li>If the problem is to prove the identity, then I think the right side should be {{{1-2sec^2(k)}}}, not what you posted.</li></ul>