Make a rough sketch of the region {(𝑥, 𝑦): 0 ≤ 𝑦 ≤ x^2, 0 ≤ 𝑦 ≤ 𝑥, 0 ≤ 𝑥 ≤ 2} and find the area of the region using integration

 

Slide6.JPG

Slide7.JPG
Slide8.JPG
Slide9.JPG
Slide10.JPG Slide11.JPG Slide12.JPG Slide13.JPG Slide14.JPG

 


Transcript

Question 32 Make a rough sketch of the region {(𝑥, 𝑦): 0 ≤ 𝑦 ≤ 𝑥^2, 0 ≤ 𝑦 ≤ 𝑥, 0 ≤ 𝑥 ≤ 2} and find the area of the region using integrationHere, 𝟎≤𝒚≤𝒙^𝟐 𝑦≥0 So it is above 𝑥−𝑎𝑥𝑖𝑠 𝑦=𝑥^2 i.e. 𝑥^2=𝑦 So, it is a parabola 𝟎≤𝒚≤𝒙 𝑦≥0 So it is above 𝑥−𝑎𝑥𝑖𝑠 𝑦=𝑥 It is a straight line Also 𝟎≤𝒙≤𝟐 Since 𝑦≥0 & 0≤𝑥≤2 We work in First quadrant with 0≤𝑥≤2 So, our figure is Finding point of intersection P Here, P is the point of intersection of parabola and line Solving 𝑦=𝑥^2 & 𝑦=𝑥 𝑥^2=𝑥 𝑥(𝑥−1)=0 So, 𝑥=0 , 𝑥=1 For 𝒙 = 0 𝑦=𝑥=1 So, O(0 , 0) For 𝒙 = 1 𝑦=𝑥=1 So, P(1 , 1) Finding area Area required = Area OPQRST Area OPSRQ = Area OPT + Area PQRS Area OPT Area OPT =∫_0^1▒〖𝑦 𝑑𝑥〗 𝑦→ Equation of Parabola 𝑦=𝑥^2 ∴ Area OPQT =∫_0^1▒〖𝑥^2 𝑑𝑥〗 =[𝑥^3/3]_0^1 =[1^3/3−0^3/3] =1/3−0 =𝟏/𝟑 square units Area PQRS Area QRST=∫_1^2▒〖𝑦 𝑑𝑥〗 Here, 𝑦→ equation of line QP 𝑦=𝑥 ∴ Area QRST=∫_1^2▒𝑥 𝑑𝑥 =[𝑥^2/2]_1^2 =[2^2/2−1^2/2] =2−1/2=𝟑/𝟐 square units Thus, Area Required = Area OPQT + Area QPST = 1/3+3/2 = (2 + 9)/6 = 𝟏𝟏/𝟔 square units

Ask a doubt
Davneet Singh's photo - Co-founder, Teachoo

Made by

Davneet Singh

Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.