设y=[cos (1/x)]^3,则dy=如题………………

来源:学生作业帮助网 编辑:作业帮 时间:2024/09/05 22:01:55
设y=[cos (1/x)]^3,则dy=如题………………
x){n_mtr~~flӎ)}!"}|85ِom1HTV@83SĨqFXUFՁԀ )6yv sl~gؼhc} Z(N$t}Y .nPX0ւiBr8u@mZH

设y=[cos (1/x)]^3,则dy=如题………………
设y=[cos (1/x)]^3,则dy=
如题………………

设y=[cos (1/x)]^3,则dy=如题………………
y'=3[cos(1/x)]^2*[cos(1/x)]'
..=3[cos(1/x)]^2*[-sin(1/x)]*(1/x)'
..=3[cos(1/x)]^2*[-sin(1/x)]*(-1/x^2)
..=3[cos(1/x)]^2[sin(1/x)]/x^2
所以dy=3[cos(1/x)]^2[sin(1/x)]/x^2 dx

结果如下:
[3/(x^2)]*[cos(1/x)]^2*sin(1/x)dx

dy=3[cos(1/x)]^2*[-sin(1/x)]*(-1)x^(-2)
=-3[cos(1/x)]^2*[-sin(1/x)]*x^(-2)

(3*cos(1/x)^2*sin(1/x)/x^2)dx

dy=3[cos(1/x)]^2*[sin(1/x)]/x^2 dx