Analyzing the Setup
Welcome, fellow explorer of the mathematical landscape. Today, we are mapping a territory defined by three boundaries: the exponential growth of y=ex, the reflective nature of the modulus function y=∣ex−1∣, and the vertical wall of the y-axis, x=0.
To find the area trapped between them, we must first understand the "personality" of these functions.
Decoding the Modulus
Imagine the function y=∣ex−1∣ as a mirror. For x≥0, ex≥1, so the modulus does nothing—it remains ex−1.
For x<0, the value ex−1 is negative. The modulus acts like a mirror, reflecting that negative portion across the x-axis to become 1−ex. This is the crucial realization: the behavior of our boundary changes exactly at the y-axis.
Finding the Hidden Intersection
Now, we hunt for the intersection by setting ex=∣ex−1∣. As discussed, for x>0, there is no intersection.
For x<0, we solve the equation ex=1−ex. This leads us to:
Taking the natural logarithm of both sides, we find our boundary point: x=ln(21), which is −ln2. We have successfully defined our limits of integration: from −ln2 to 0.
The Integral of Elegance
With our limits set, we construct the integral for the area A. The area is the accumulation of the vertical distance between the upper curve y=ex and the lower curve y=1−ex.
The integral becomes:
Look at how the expression simplifies. The negative sign distributes, and we are left with:
This is the moment of truth. We integrate term by term, where the integral of 2ex is 2ex and the integral of 1 is x. We are left with the evaluation:
Final Calculation
Now, we apply the Fundamental Theorem of Calculus. At the upper limit x=0, we have:
At the lower limit x=−ln2, we have 2e−ln2−(−ln2). Since e−ln2=eln21=21, this simplifies to:
Subtracting the lower limit value from the upper limit value, we get:
And there it is! The final area is 1−ln2. Remember, the modulus function is not an obstacle; it is a signpost telling you where to split your journey.