f dx/ sqrt (a2 - x2) = arcsin x/|a| + c
f dx/ sqrt (x2 + a) = ln | x + sqrt (x2 + a) | + c
f sqrt (a2 - x2) dx = a2/2 arcsin x/|a| + x/2 sqrt (a2 - x2) + c
f sqrt (x2 + a) dx = (1/2)*x sqrt (x2 + a) + (1/2)*a ln |x + sqrt (x2 + a) | + c
f sinnxdx = - 1/n sinn-1 xcosx + n-1/n f sinn-2xdx
fcos nxdx = 1/n cosn-1xsinx + n-1/n f cosn-2xdx
sinx,cosx.../tgx,sinx...
T = tg x/2
T = tg x/2 => x =2arctgt => dx = 2dt/ 1 + t2
sinx = 2t/ 1+t2 , cosx = 1 - t2 / 1 + t2 , tgx = 2t/1-t2 , ctgx = 1- t2 / 2t
sin2x, cos2x, sinxcosx
t=tgx x=arctgt dx=1/1+t2dt sin2x=t2/1+t2 cos2t=1/1+t2