Evaluate the following integral cotx dx Select one: x cot""x -In(1+x?)+c 2 x cot-1x +2/1+x² + C х cot 1x - Im/ 1+x2 +с x cot-1x +In/ 1+x² + C None

Show that (1 + i)95 = 247(1 - i).

Evaluate Stanª tan4 x sec4 xdr +C

et △ABC be a triangle in S^2 (the two-dimensional sphere). Let the dual point C'∈S^2 of C be defined by the following three conditions:(i) d(C' , A)=π/2(ii) d(C' , B)=π/2(iii) d(C' , C)≤π/2A' and B' are defined analogously. Thus we get a dual triangle △A' B' C'. More precisely, △ABC is a non-degenerate triangle, andit follows (you may assume) that △A' B' C' is too.(question) Are there triangles △ABC in S^2 identical to their own dual △A'B'C'?   I would be very thankful if you could provide some explanation with the steps, thank you in advance.