Question

求f(x)=arccos1/2(x^2-x)的定义域?

Answer 1

f(x)=arccos1/2(x^2-x)

-1≤1/2(x^2-x)≤1

-2≤x^2-x≤2

1.

x^2-x≥-2

x^2-x+2≥0

因为△=1-4×2=-7