9
y`=1/x-3=0
1/x=13
x=1/13∈[1/26;5/26]
y(1/26)=ln0,5-0,5+10=9,5+ln0,5≈8,9
y(1/13)=ln1-1+10=0+9=9 наиб
y(5/26)=ln2,5-2,5+10=6,5+ln2,5≈7,4
10
3/sinx-1/sin²x=2
sinx≠0⇒x≠πk,k∈z
sinx=a
3/a-1/a²=2
2a²-3a+1=0
D=9-8=1
a1=(3-1)/4=1/2
sinx=1/2
x=π/6+2πk U x=5π/6+2πk
-2π≤π/6+2πk≤-π/2 U -2π≤5π/6+2πk≤-π/2
-12≤1+12k≤-3 U -12≤5+12k≤-3
-13≤12k≤-4 U -17≤12k≤-8
-13/12≤k≤-1/3 U -17/12≤k≤-2/3
k=-1⇒x=π/6-2π=-11π/6 U x=5π/6-2π=-7π/6