急 ! F4 數 Function 3

As the value in √ sign should be greater than or equal to 0

3x - 1> = 0 and x^2 + 1 >= 0

x >=1/3 or x^2 >= -1

So the domain is x >= 1/3 where x are real number

首先 開方(x^2 +1) 是分母 ，所需考慮的domain 就在這兒開方(x^2 +1) ≠ 0 <--- 2邊平方
(x^2 +1)≠ 0
x^2 ≠ -1
x can be all real root
原因是只有分母唔等於0 , 個f(x)就唔會undefined!就有得計
所考慮的不是分子， 分子就算0了 最後答案F(x) =0 也是計到個值!
所以x既domain should be all real x


答案並不是 x>=1/3!!!

When x ＞0 , F(x) is a real no.


therefore the largest domain is When x ＞0