A) y=27x^5+19x+61
Применим (uv)'=u'v+uv'
(u^n)'=nu^(n-1)
(cu)'=cu', c-const
y'=27*5x^4+19=135x^4+19
b) (u/v)'=(u'v-uv')/v^2
y'=(cos x-x(-sin x))/(cos^2 x)
2. y=19sin x, y'=19cos x
y'(-П/4)=19cos (-П/4) = =(19(2)^1/2)/2
3. y'=1/3•3x^2-14x+38=
=x^2-14x+38, y'=-2
x^2-14x+40=0, D=196-160=
+36, корни уравнения 4 и 10.
Ответ: y'(4)=y'(10)=-2