2
f`(x)=(1*√(x²-8)-2(x-4)/2√(x²-8))/(x²-8)=(x²-8-x+4)/√(x²-8)³=(x²-x-4)/√(x²-8)³
f`(3)=(9-3-4)/√(9-8)³=2/1=2
3
f`(x)=6x²+5x-1=0
D=25+24=49
x1=(-5-7)/12=-1 x2=(-5+7)/12=1/6
+ _ +
----------------(-1)------------------(1/6)-----------------
возр убыв возр
4
F(x)=5ln(x+3)-7√(x+18)+C
5ln1-7√16+C=-30
5*0-7*4+C=-30
C=-30+28
C=-2
F(x)=5ln(x+3)-7√(x+18)-2