1. y = √ (3x+1)
更新1:
The answer is yes But..... When x = 8 y = √ ( 3(8) + 1) =√ 25 = +5 or = -5 that means one x has 2 values of y so that is not a function am i correct?
更新2:
Why it cannot be -5? -5 x -5 = 25 5 x 5 = 25
F.4 Function
回答 (3)
2009-12-30 6:04 am
✔ 最佳答案
y = √ (3x+1) for x >= 0
√ (3x+1) >= √ [(3(0) + 1]
√ (3x+1) >= 1
y >= 1
2009-12-29 22:21:01 補充：
Your concept is not clear !
For any x , √x is positive.
2009-12-29 22:22:36 補充：
x^2 = 25
x = +√ 25 or - √ 25
2009-12-29 22:23:43 補充：
√ 25 = 5 only
not = - 5
2009-12-29 23:15:59 補充：
You remamber that :
The roots of x^2 = x or - x
;
But the answer of √ x^2 is = |x| only!
For example : √(- 5)^2 = |-5| = 5 only
Hope can help you!!
2009-12-31 2:59 am
2009-12-30 7:13 am
√ 係正根咁解.負根要咁樣表示 -√
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