Question

The value of the integral $\int\limits^{0.9}_{{0}}[x - 2 [x]] dx ,$ where $[.]$ denotes the greatest integer function is

• A. $0.9$
• B. $1.8$
• C. $-0.9$
• D. $0$

Answer 1

Answer: (D)

$0$

Answer 2

Since $\int\limits^{a}_{{0}}[x]=0$ where $0 \le a \le 1$ $\therefore$ $\int\limits^{0.9}_{{0}}[x-2[x]]dx = 0$