Finding area between 2 functions

  • Context: MHB 
  • Thread starter Thread starter tmt1
  • Start date Start date
  • Tags Tags
    Area Functions
Click For Summary
SUMMARY

The discussion focuses on finding the area between the curves defined by the equations \(x = 2y^2\) and \(x = 1 - y\), as well as \(x = 2 - y^2\) and \(x = y^2 - 2\). The intersection points for the first set of equations were calculated incorrectly, with the correct intersection points being \(y = \frac{1}{2}\) and \(y = -1\). For the second set, the area calculation was initiated correctly, but the final answer was miscalculated, with the correct area being \(\frac{16\sqrt{2}}{3}\).

PREREQUISITES
  • Understanding of calculus, specifically integration techniques.
  • Familiarity with finding intersection points of functions.
  • Knowledge of quadratic equations and their solutions.
  • Experience with definite integrals and area calculations between curves.
NEXT STEPS
  • Study the method for finding intersection points of curves in calculus.
  • Learn about definite integrals and their applications in calculating areas between functions.
  • Explore the use of the quadratic formula for solving equations like \(2y^2 + y - 1 = 0\).
  • Practice problems involving area calculations between different types of curves.
USEFUL FOR

Students and educators in calculus, mathematicians focusing on integration and area calculations, and anyone looking to improve their understanding of curve intersections and area determination between functions.

tmt1
Messages
230
Reaction score
0
1.

I have to find the area between

$x = 2y^2$
and
$x = 1 - y$

I find the intersection points

$ 1 -y = 2y^2$

$2y^2 + y - 1= 0 $

$(2y - 1)(y + 1)= 0$

so y = 1 and -1

However, x = y - 1 is not a vertical line so I am not sure how 1 and -1 can be intersections. Also, when I plug these numbers into the original equation they don't equate, so what am I doing wrong here?

1. I have another problem for finding the area between

$x = 2 - y^2$

and
$x = y^2 - 2$

I found that the points of intersection are y =$ +/- \sqrt{2}$ and the greater function is $ x = 2 - y^2$ so

$\int_{-\sqrt{2}}^{\sqrt{2}} 4 - 2y^2 \,d$

then

$\left[4y - \frac{2y^3}{3}]\right]_1^3$

and

$[4\sqrt{2} - \frac{2\sqrt{8}}{3}] - [- 4 \sqrt{2} + \frac{4 \sqrt{8}}{3}]$

and then

$4\sqrt{2}$

However the answer is $\frac{16\sqrt{2}}{3}$
 
Physics news on Phys.org
tmt said:
1.

I have to find the area between

$x = 2y^2$
and
$x = 1 - y$

I find the intersection points

$ 1 -y = 2y^2$

$2y^2 + y - 1= 0 $

$(2y - 1)(y + 1)= 0$

Correct up to here. Now notice that $\displaystyle \begin{align*} 2y - 1 = 0 \implies 2y = 1 \implies y = \frac{1}{2} \end{align*}$. The other solution y = -1 is fine...
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 9 ·
Replies
9
Views
1K
  • · Replies 20 ·
Replies
20
Views
4K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 12 ·
Replies
12
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K