Question

[Nguyen Tam]

Tìm tập xác định

a) y=\(\dfrac{x-1}{\left(2x^2-5x+2\right)\left(x^3+1\right)}\)

b)y=\(\dfrac{3x\left(x^2-1\right)}{\left(x^2+2x+2\right)\left(x+5\right)}\)

c)y=\(\dfrac{x-1}{x^4-1}\)

d)\(\dfrac{1}{x^4+2x^2-3}\)

e)y=\(\dfrac{x+2}{x^3+2x^2-3x-6}\)

g) y=\(\sqrt{4-x}+\sqrt{5x+1}\)

h)y=\(\dfrac{1+x}{\left(x^2+2x-8\right)\sqrt{x-1}}\)

i)y=\(\dfrac{\sqrt{5-2x}}{\left(2x^2-5x+2\right)\sqrt{x-1}}\)

Answer 1

[Nguyễn Lê Phước Thịnh]

a: ĐKXĐ: \(\left(2x^2-5x+2\right)\left(x^3+1\right)< >0\)

=>(2x-1)(x-2)(x+1)<>0

hay \(x\notin\left\{\dfrac{1}{2};2;-1\right\}\)

b: ĐKXĐ: x+5<>0

=>x<>-5

c: ĐKXĐ: x⁴-1<>0

hay \(x\notin\left\{1;-1\right\}\)

d: ĐKXĐ: \(x^4+2x^2-3< >0\)

=>\(x\notin\left\{1;-1\right\}\)