The area of the region enclosed by the curves y=ex,y=∣ex−1∣ and y-axis is:
(A)1+loge2
(B)loge2
(C)2loge2−1
(D)1−loge2✓ Correct
Answer: (D)
Solution
The curve y=∣ex−1∣ equals ex−1 for x≥0 and 1−ex for x<0. Since y=ex is always above ex−1 (they never meet for x≥0), the curves y=ex and y=∣ex−1∣ can only intersect where x<0:
ex=1−ex⇒2ex=1⇒x=−ln2.
For −ln2<x<0, ex>1−ex (check x=−ln2/2: ex≈0.71 vs 1−ex≈0.29), so the region enclosed by y=ex (top), y=∣ex−1∣=1−ex (bottom), and the y-axis (x=0, right boundary) runs from x=−ln2 to x=0: