- 19
-
[ ]
- A.5
- B.3
- C.-3
- D.-5
- A.Y*=(Ax+B)e<sup>x</sup>
- B.y*=x(Ax+B)e<sup>x</sup>
- C.y*=Ax<sup>3</sup>e<sup>x</sup>
- D.Y*=x<sup>2</sup>(Ax+B)e<sup>x</sup>
- A.单调减少
- B.单调增加
- C.为常量
- D.不为常量,也不单调
- A.2
- B.-2
- C.3
- D.-3
- 25
-
( )
- A.1/2
- B.1
- C.2
- D.e
- A.2n
- B.π <img alt="" src="//img1.yqda.net/question-name/c2/87920bdc71e09aa3aef2534e843699.jpg" /> <img alt="" src="//img1.yqda.net/question-name/d6/e790c1bd25bd706f00bd7b17bb84f9.jpg" />
- 27
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( )
- A.必条件收敛
- B.必绝对收敛
- C.必发散
- D.收敛但可能为条件收敛,也可能为绝对收敛
- 28
-
( )
- A.x2+cosy
- B.x2-cosy
- C.x2+cosy+1
- D.x2-cosy+1