Lim┬(x→0)〖(1+x-x^2)/(〖2x〗^2+5x+4)〗 =
=lim┬(x→0)〖(1+x-x^2):x^2/(〖2x〗^2+5x+4):x^2〗=
=lim┬(x→0)〖(1/x^2+x/x^2-x^2/x^2)/(4x^2/x^2+5x/x^2+4/x^2)〗=
= lim┬(x→0))〖(1/x^2+1/x-1)/(4+5/x+4/x^2)〗=-1/4
cos 200 градусов = - cos (180 + 20) градусов = - cos 20 градусов = -0,9397
10sin38/sin19cos19 = 20sin38/sin38 = 20
Ответ: 20.