电大微积分初步考试小抄 一、填空题 ⒈函数xxf51)(的定义域是 (-∞,5).5-x >0 →x <5 ⒉xxx1sinlim 1 . 1sinlimxxx,01 xx时, ⒊已知xxf2)(,则)(xf = 2ln22)(x . ⒋若cxFxxf)(d)(,则xxfd)32(CxF )32(21. ⒌微分方程yxxyyxesin)(4的阶数是 三阶 . y 6
函数)2ln(1)(xxf的定义域是(-2,-1)U(-1,∞) 122-1ln)2(ln2-x02ln02xxxxx,>,>,> ∴1- 2-x|且>x 7
xxx2sinlim0 2 . 2112122sinlim2sinlim00xxxxxx 21:222sinlim0xxx 8
若y = x (x – 1)(x – 2)(x – 3),则y (0) = -6 y=x(x-1)(x-2)(x-3)=(x2-x)(x2-5x+6)=x4-5x3+6x2-x3+5x2-6x =x4-6x3+11x2-6x , 622184y23xxx (把0 带入 X),6)0( y 9
xx ded2dxxe2 )()(xfdxxf)(或dxxfdxxfd)())(( 10
微分方程1)0(,yyy的特解为 y=ex
yy ydxdy dxdydxydyy1两边积分 ecxy又 y(0)=1 (x=0 , y=1) cxyln 010cec, 11
函数24)2ln(1)(xxxf的定义域是 2,1-1-2-, 1