The range of f(x)=4sin-1(x2x2+1) is [2023]
(1)
Given, 4sin-1(x2x2+1)
x2x2+1=x2+1-1x2+1=1-1x2+1
x2≥0; x2+1≥1 ∴ 0<1x2+1≤1⇒-1≤-1x2+1<0;
0≤1-1x2+1<1; 0≤4sin-1(x2x2+1)<2π