We know that the greatest integer function is discontinuous at integral points.
−5<2x<5
⇒[2x]=−5,−4,−3,−2,−1,0,1,2,3,4, are the integer values.
At x=0, f(0+)=f(0)=f(0−)=0, which means that function is continuous at x=0.
∵x=−10⇒2x=−5
Hence, the function is discontinuous at points −4,−3,−2,−1,1,2,3,4
The number of values is 8 .