Question
Mathematics Question on Definite Integral
Let [t] denote the greatest integer less than or equal to t Then the value of the integral −3∫101([sin(πx)]+e[cos(2πx)])dx is equal to
A
e52(1−e)
B
e52
C
e52(2+e)
D
e104
Answer
e52
Explanation
Solution
−3∫101([sinπx]+e[cos2πx])dx
520∫2([sinπx]+e[cos2πx])dt
π520∫2π([sint]+e[cos2t])dt
π520∫2π([sint]dt+0∫2πe[cos2t]dt)
I1=0∫2π[sint]dt
Using King
I1=0∫2π[−sint]dt
2I1=0∫2π(−1)dt=−2π
I1=−π
I2=20∫πe[cos2t]dt
=2.20∫π/2e[cos2t]dt
=4(0∫π/4e0⋅dt+π/4∫π/2e−1dt)
4(4π+e−1(4π))=π(1+e−1)
I=π52(−π+π+πe−1)=e52