The domain of the function f(x)= log3 (2x+1) is:
a) Df= {xeR: 1 ≤ x < 2}
b) Df={xeR: x>- 1/2}
c) Df={xeR: -1 ≤ x < 2 }
Which one of these three is right?
what is the correct domain of the function ?
2016-12-05 3:00 pm
回答 (2)
2016-12-05 3:02 pm
✔ 最佳答案
the argument of a logarithm must be positive.2x+1 > 0
x > -½
domain = {x∈ℝ: x > -½}
2016-12-05 3:13 pm
2x+1 is within the log so must be > 0
2x+1 > 0
2x > -1
x > -1/2
domain is (-1/2, infinity)
2x+1 > 0
2x > -1
x > -1/2
domain is (-1/2, infinity)
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