Question
Question: Evaluate : \(\int _ { a } ^ { b } \frac { | x | } { x }\) dx, a \< b -...
Evaluate : ∫abx∣x∣ dx, a < b -
A
|a| – |b|
B
|b| + |a|
C
|b| – |a|
D
None of these
Answer
|b| – |a|
Explanation
Solution
Let I = dx
Case I : When 0 < a < b
then I = dx =
. dx =
= b – a
= |b| – |a| … (1)
Case II : When a < 0 < b
then I = –. dx +
. dx
= – (0 – a) + (b – 0)
= b + a
= |b| – |a| … (2)
Case III : When a < b < 0
then I = . dx = – (b – a) = – b + a
= |b| – |a| … (3)
It is clear from (1), (2) and (3) we get
dx = |b| – |a|.