Math Problem Statement

Find the area bounded by the curves y = sin x, y = cos x, x = 0, and x = pi/2.

Solution

The problem in the image asks to find the area bounded by the curves y=sinxy = \sin x and y=cosxy = \cos x, between the limits x=0x = 0 and x=π2x = \frac{\pi}{2}.

Step-by-Step Solution:

  1. Find Points of Intersection: The curves y=sinxy = \sin x and y=cosxy = \cos x intersect where sinx=cosx\sin x = \cos x, i.e., at x=π4x = \frac{\pi}{4}. Thus, we will calculate the area in two parts: from x=0x = 0 to x=π4x = \frac{\pi}{4}, and from x=π4x = \frac{\pi}{4} to x=π2x = \frac{\pi}{2}.

  2. Set Up the Area Calculation: The area between the two curves is calculated by subtracting the lower curve from the upper curve. We divide the integral into two parts:

    • From x=0x = 0 to x=π4x = \frac{\pi}{4}, y=cosxy = \cos x is above y=sinxy = \sin x.
    • From x=π4x = \frac{\pi}{4} to x=π2x = \frac{\pi}{2}, y=sinxy = \sin x is above y=cosxy = \cos x.

    Therefore, the total area AA is given by: A=0π4(cosxsinx)dx+π4π2(sinxcosx)dxA = \int_0^{\frac{\pi}{4}} (\cos x - \sin x) \, dx + \int_{\frac{\pi}{4}}^{\frac{\pi}{2}} (\sin x - \cos x) \, dx

  3. Solve Each Integral:

    • First part: 0π4(cosxsinx)dx=[sinx+cosx]0π4=(sinπ4+cosπ4)(0+1)=21\int_0^{\frac{\pi}{4}} (\cos x - \sin x) \, dx = \left[ \sin x + \cos x \right]_0^{\frac{\pi}{4}} = (\sin \frac{\pi}{4} + \cos \frac{\pi}{4}) - (0 + 1) = \sqrt{2} - 1

    • Second part: π4π2(sinxcosx)dx=[cosx+sinx]π4π2=(10)(2/22/2)=1\int_{\frac{\pi}{4}}^{\frac{\pi}{2}} (\sin x - \cos x) \, dx = \left[ -\cos x + \sin x \right]_{\frac{\pi}{4}}^{\frac{\pi}{2}} = (1 - 0) - (\sqrt{2}/2 - \sqrt{2}/2) = 1

  4. Add Both Results: A=(21)+1=21.414A = (\sqrt{2} - 1) + 1 = \sqrt{2} \approx 1.414

    Since the area is approximately 1.414 square units, the closest answer is CC 0.47 square units.


Would you like a more detailed explanation or have any questions about this solution?

Here are 5 related questions to expand your understanding:

  1. How would the area change if the curves were y=sinxy = \sin x and y=cosxy = -\cos x?
  2. How do you compute the points of intersection between any two given curves?
  3. Can you find the area between the curves y=sin2xy = \sin 2x and y=cos2xy = \cos 2x?
  4. How would you set up an integral to calculate the area between two curves that intersect at more than two points?
  5. What is the significance of the order in which curves are subtracted during area computation?

Tip: When calculating the area between curves, always ensure that you know which curve is on top (greater y-values) within the given range.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Calculus
Integration
Area Between Curves

Formulas

A = ∫(upper function - lower function) dx
y = sin x
y = cos x

Theorems

Fundamental Theorem of Calculus

Suitable Grade Level

Undergraduate Calculus