Let z=x+ 1.
x=z- 1
f(z)=z- 1+cos(z- 1)
f( 1)= 1- 1+cos( 1- 1)
=0+cos0
= 1
2、B
Xsin 1/x When x→0, x is infinitesimal, while sin 1/x is a bounded function, and the product of infinitesimal and bounded function is infinitesimal.
3、B
Function continuity → function limit exists, which is a necessary condition for function continuity.
4、D
y'=3(x- 1)^2
y"=6(x- 1)
y"=0
6(x- 1)=0
x= 1
y=( 1- 1)^3=0
y " & gt0:x & gt; 1
y " & lt0:x & lt; 1
Therefore, (1, 0) is the inflection point.
17、
( 1) f(x)=2sinxsin(x+π/6)
=cos[(x+π/6)-x]-cos[(x+π/6)+x]
=cosπ/6-cos(2x+π/6)
=√3/2-cos(2x+π/6)
T=2π/2=π
2kπ= & lt; 2x+π/6 & lt; =π+2kπ
-π/6+2kπ= & lt; 2x & lt=5π/6+2kπ
Monotone increasing interval: -π/ 12+kπ =
(2) x∈[0,π/2]
2x+π/6∈[π/6,7π/6]
cos(2x+π/6)∈[- 1,√3/2]
√3/2-cos(2x+π/6)∈[0, 1+√3/2]
Range: [0, 1+√3/2]