The value of the integral 0 e(x)x2+4 dx is:
- e(2)2
- e(2)4
- 1+ e(2)
- 2+ e(2)
Answer
(2) e(2)4
Solution
Put x=2t, dx=2 dt:
I= 0 e 2+ e t4 (1+t2 ) 2 dt= 12 0 e 21+t2dt+ 12 0 e t1+t2dt
Let J= 0 e t1+t2dt; put t= 1u, dt=- duu2:
J= 0 - e u1+ 1u2 (- duu2 )=- 0 e u1+u2du=-J J=0
I= e 22 [ -1t ]0 = e 22 2= e(2)4
Answer: (2)