у =
у' = 15**(1-10x)' = 15**(-10) = -150*
y'=15*(1-10x)¹⁴*(-10)y'=-150*(1-10x)¹⁴
cos2x=3/4
2x=+-arccos3/4 +2nk
x=(+-arccos3/4)/2+nk