题目内容
(1)求极限
=______,
(2)求导数(23x-x3-cos3x)′=______.
lim |
x→9 |
2-log3x |
x-9 |
(2)求导数(23x-x3-cos3x)′=______.
(1)
=
=
=
=
=
(2)(23x-x3-cos3x)′=(23x-x3)′-(cos3x)′=23x-x3•(3-3x2)•ln2+3sin3x
故答案为(1)
;(2)23x-x3•(3-3x2)•ln2+3sin3x
lim |
x→9 |
2-log3x |
x-9 |
lim |
x→9 |
| ||
x-9 |
lim |
x→9 |
2 |
xlnx |
2 |
9ln9 |
1 |
9ln3 |
log3e |
9 |
(2)(23x-x3-cos3x)′=(23x-x3)′-(cos3x)′=23x-x3•(3-3x2)•ln2+3sin3x
故答案为(1)
log3e |
9 |
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