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Question: The value of \(\int _ { \pi } ^ { 2 \pi } [ 2 \sin x ] d x\) where ![](https://cdn.pureessence.tech/...

The value of π2π[2sinx]dx\int _ { \pi } ^ { 2 \pi } [ 2 \sin x ] d x where represents the greatest integer function, is

A

π- \pi

B

2π- 2 \pi

C

5π3- \frac { 5 \pi } { 3 }

D

5π3\frac { 5 \pi } { 3 }

Answer

5π3- \frac { 5 \pi } { 3 }

Explanation

Solution

π2π[2sinx]dx=ππ+(π/6)(1)dx+π+(π/6)π+(π/2)(2)dx\int _ { \pi } ^ { 2 \pi } [ 2 \sin x ] d x = \int _ { \pi } ^ { \pi + ( \pi / 6 ) } ( - 1 ) d x + \int _ { \pi + ( \pi / 6 ) } ^ { \pi + ( \pi / 2 ) } ( - 2 ) d x

+π+(π/2)π+(π/2)+(π/3)(2)dx+π+(π/2)+(π/3)2π(1)dx+ \int _ { \pi + ( \pi / 2 ) } ^ { \pi + ( \pi / 2 ) + ( \pi / 3 ) } ( - 2 ) d x + \int _ { \pi + ( \pi / 2 ) + ( \pi / 3 ) } ^ { 2 \pi } ( - 1 ) d x

=π62[π2π6]2[π3]1[π2π3]= - \frac { \pi } { 6 } - 2 \left[ \frac { \pi } { 2 } - \frac { \pi } { 6 } \right] - 2 \left[ \frac { \pi } { 3 } \right] - 1 \left[ \frac { \pi } { 2 } - \frac { \pi } { 3 } \right]

=π62π32π3π6= - \frac { \pi } { 6 } - \frac { 2 \pi } { 3 } - \frac { 2 \pi } { 3 } - \frac { \pi } { 6 } =π68π6π6=10π6=5π3= - \frac { \pi } { 6 } - \frac { 8 \pi } { 6 } - \frac { \pi } { 6 } = - \frac { 10 \pi } { 6 } = - \frac { 5 \pi } { 3 } .