Math problem. Find interval with solution. Thanks.?
回答 (2)
2016-01-20 5:43 am
✔ 最佳答案
f(x) = (2 - x) eˣf'(x) = (1 - x) eˣ
f''(x) = - x eˣ
f(x) is decreasing when f'(x) = (1 - x) eˣ < 0
(1 - x) eˣ < 0
(1 - x) < 0 ...... ( Since eˣ > 0 )
x > 1
The interval is (1,∞)
∴ D. (1,∞)
2016-01-27 5:25 am
f"(x)=0
-x eˣ =0
x=0 or eˣ=0 (delete)
-------x<0 x=0 x>0
f'(x) + 0 -
D
-x eˣ =0
x=0 or eˣ=0 (delete)
-------x<0 x=0 x>0
f'(x) + 0 -
D
收錄日期: 2021-04-18 14:23:19
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