Animated Solution for Mathematics - Definite Integration: Find the area of the region bounded by the curve C:y=tanx, tangent drawn to C at x=4π and the x-axis.
Visualized Solution
Visualize the Curve and Point P
Curve C:y=tanx
At x=4π, y=tan(4π)=1
Point of tangency: P(4π,1)
Finding the Slope of the Tangent
To find the equation of the tangent, we first need its slope.
The slope m is given by the derivative dxdy at x=4π.
Differentiating the Curve
Differentiating y=tanx with respect to x:
dxdy=sec2x
Evaluating the Slope at P
Substitute x=4π into the derivative:
m=sec2(4π)
m=(2)2=2
Equation of the Tangent Line
Using the point-slope form: y−y1=m(x−x1)
Substitute P(4π,1) and m=2:
y−1=2(x−4π)
Finding the x-intercept
The tangent intersects the x-axis where y=0.
0−1=2(x−4π)
−21=x−4π
Coordinates of the Intercept
x=4π−21=4π−2
Let this point be L(4π−2,0)
Identifying the Required Region
We need the area bounded by:
Curve C:y=tanx
Tangent line PL
The x-axis
Let's drop a perpendicular from P to the x-axis at M(4π,0).
Strategy for Area Calculation
Required Area = (Area under curve from x=0 to x=4π) − (Area of △PLM)
Integral for Area Under Curve
Area under curve A1=∫0π/4tanxdx
Evaluating the Integral
A1=[ln∣secx∣]0π/4
A1=ln(sec4π)−ln(sec0)
A1=ln(2)−ln(1)=21ln2
Dimensions of Triangle PLM
Base LM=xM−xL=4π−4π−2
Base LM=4π−(π−2)=42=21
Height PM=yP=1
Area of Triangle PLM
Area of △PLM=21×Base×Height
Area =21×21×1=41
Final Area Calculation
Required Area =A1−Area of △PLM
Required Area =21ln2−41
Required Area =21[ln2−21] sq. units
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The Sigma Insight: Area Bounded by Curves
Solution Diagram
Analyzing the Setup
We are tasked with finding the area of a region bounded by the curve y=tanx, the tangent line drawn to this curve at x=4π, and the x-axis. This problem requires a precise combination of coordinate geometry and integral calculus.
The Point of Tangency
First, we identify the point of tangency on the curve y=tanx. At x=4π, the function value is:
y=tan(4π)=1
Thus, our point of tangency, P, is located at (4π,1). This point serves as the anchor for our tangent line.
The Slope and the Tangent Line
To define the tangent line, we calculate the derivative of the function y=tanx, which is dxdy=sec2x. Evaluating this at x=4π gives the slope m:
m=sec2(4π)=(2)2=2
Using the point-slope form y−y1=m(x−x1), the equation of the tangent line is:
y−1=2(x−4π)
The Geometric Trap
The tangent line intersects the x-axis at point L. Setting y=0 in the tangent equation, we solve for x:
−1=2(x−4π)⇒x=4π−21
By dropping a perpendicular from P to the x-axis at M(4π,0), we form a right-angled triangle PLM. The base LM is 4π−(4π−21)=21, and the height is 1.
The area of triangle PLM is:
Area△=21×base×height=21×21×1=41
The Integration
We now calculate the area under the curve y=tanx from x=0 to x=4π using a definite integral:
∫0π/4tanxdx=[ln∣secx∣]0π/4
Evaluating this expression, we obtain:
ln(sec4π)−ln(sec0)=ln(2)−ln(1)=21ln2
Final Calculation
The target area is the region under the curve minus the area of the triangle PLM. Subtracting the triangle's area from the integral result, we get: