1=2-(2x?1)edx =2-(3e?1)+2e0?xx10=
=3?3e?2e?2?1?e。 (7分)
7.解:
F?x,y??2x2?2xy?y2?0
?4x?2y?2xdydy?2y?0dxdxdy?2(2x?y)?2(x?y)?0dxdy2x?yx??????1dxx?yx?yxdy(x?y)?x?x?x(x?y)?x(1?)d2yx?ydx????22dx(x?y)(x?y)2(x?y)2?x22x2?2xy?y2?????033(x?y)(x?y)(7分)
8.解:
(3分)
y?1111x?1x?12x?13x?1n?[]?[1??()?()???(?1)n()??]
x?1x?12222221?2n?n(x?1)=?(?1), (5分) n?12n?0收敛区间为(-1, 3). (7分)
9.解:
(
ysinx (5分) )'?cosxcos2xy?Ccosx?1(其中C为任意常数) (7分)
2210.解:直线x?1与圆x?y?4的交点是P1(1,3),P2(1,?3), (2分) 右面部分绕y轴旋转一周的所得几何体的体积.
3V???32[(4?y)?1]dy (5分) ?3y3)?43? (7分) =2?(3y?30四.综合题:
11.解:?cosnxcosmxdx=?[cos(n?m)x?cos(n?m)x]dx (3分)=
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?????2, n?m?0?n?m?0 (10分) ??, ?0, n?m??4322.证明:证明:(1)考虑函数F(x)?ax?bx?cx?dx, (2分) F(x)在[0,1]上连续,在(0,1)内可导,F(0)?F(1)?0, (4分)
' 由罗尔定理知,存在??(0,1),使得F(?)?0,即
F'(?)?f(?)?0,就是f(?)?4a?3?3b?2?2c??d?0,
所以函数f(x)在(0,1)内至少有一个根. (7分)
'''2(2)f(x)?F(x)?12ax?6bx?2c
2222 因为3b?8ac,所以(6b)?4(12a)(2c)?36b?96ac?12(3b?8ac)?0,
f'(x)保持定号,f(x)函数f(x)在(0,1)内只有一个根. (10分)
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