SIC] foreign minus sine t j plus e raised to 3 d k. Okay, find d r by d d, and d square r formula D by dt of e raised to 80 n1 e raised to 80 into 80 foreign.04:41Um, if r of t is equal to t, square I plus e raised to t, j minus 2, cos pi t k. Find dash of t. If r of t is equal to tan inverse t plus t into cos t j minus 2 root t k, tan inverse t I plus t into cos t j minus 2 root t k.07:24Okay, helpful D by d x of tan inverse x, and then d by dx of tan inverse x is equal to 1 by 1 plus x square at the t into cosine product r. dash of t is equal to equal to tan inverse theta derivative formula. Okay, but again, sine phi by 2 one nano cos pi, [applause] is minus 2 into Uh, sine pi by four, sine pi by four, then one by root two into k n minus e two root two cancel number root two i minus root two k negative Either Promising Three markers at the point is equal to pi.13:48Okay, is equal to my factor r of t Is equal to c t i plus time t j. Uh time dj T letter written enough c t panty into i. Okay, time t derivative d by d x of tan x Is equal to c square x.14:58Um, uh, tiny is equal to c 0, tan 0. i plus c square 0 j 0 cosine square known by square [music] e raised to minus t j plus t raised to 4 k. Find find r dash of t at t is equal to 2..16:18differentiate minus 1 into j plus t raised to 484 t cube into k. I'm going to find the entire r dash of t at t is equal to two. Final t two would come either one by two i minus e raise to minus two j plus 4 into 2, cube 4 into 2, cube 1, and the 4 into 8, 4 into 8, 1 and 3 and 32 k.