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Definite Integration by properties - P2
Definite Integration by properties - P2
Last updated at December 16, 2024 by Teachoo
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Misc 31 Evaluate the definite integral ā«_1^4ā[|š„ā1|+|š„ā2|+|š„ā3|] šš„ I=ā«_1^4ā[|š„ā1|+|š„ā2|+|š„ā3|] šš„ I=ā«_1^4ā|š„ā1| šš„+ā«_1^4ā|š„ā2| šš„+ā«_1^4ā|š„ā3| šš„ Solving šš I1=ā«_1^4ā|š„ā1| šš„ We kow that |š„ā1|= {ā( (š„ā1) ššš š„ā„1@ā(š„ā1) ššš š„<1)⤠Therefore, I1=ā«_1^4ā|š„ā1| šš„ I1=ā«_1^4ā(š„ā1) šš„ I1=ā«_1^4āš„ šš„āā«_1^4ā1 šš„ I1=[š„^2/2]_1^4ā[š„]_1^4 I1=((4)^2 ā (1)^2)/2 ā [4ā1] I1=(16 ā 1)/2 ā [3] I1=15/2 ā3 I1=(15 ā 6)/2 I1=9/2 Solving šš I2=ā«_1^4ā|š„ā2| šš„ We know that |š„ā2|= {ā( (š„ā2) ššš š„ā„2@ā(š„ā2) ššš š„<2)⤠Therefore I2=ā«_1^4ā|š„ā2| šš„ I2=ā«_1^2āćā(š„ā2) ć šš„+ā«_2^4ā(š„ā2) šš„ I2=ā«_1^2ā(āš„+2) šš„+ā«_2^4ā(š„ā2) šš„ I2=ā«_1^2āćāš„ć šš„+ā«_1^2ā2 šš„+ā«_2^4āš„ šš„āā«_2^4ā2 šš„ I2=ā[š„^2/2]_1^2+2[š„]_1^2+[š„^2/2]_2^4ā2[š„]_2^4 I2=ā[(4 ā 1)/2]+2[2ā1]+[(16 ā 4)/2]ā2[4ā2] I2=ā[3/2]+2[1]+12/2ā2[2] I2= (ā 3)/2 + 2+6ā4 I2= (ā3)/2 +8ā4 I2= (ā3)/2 +4 I2= (ā 3 + 8)/2 I2= 5/2 Solving šš I3=ā«_1^4ā|š„ā3| šš„ We know |š„ā3|= {ā( (š„ā3) ššš š„ā„3@ā(š„ā3) ššš š„<3)⤠Therefore, I3=ā«_1^4ā|š„ā3| šš„ I3=ā«_1^3āćā(š„ā3) ć šš„+ā«_3^4ā(š„ā3) šš„ I3=ā«_1^3ā(āš„+3) šš„+ā«_3^4ā(š„ā3) šš„ I3=ā«_1^3āćāš„ć šš„+ā«_1^3ā3 šš„+ā«_3^4āš„ šš„āā«_3^4ā3 šš„ I3=ā[š„^2/2]_1^3+3[š„]_1^3+[š„^2/2]_3^4ā3[š„]_3^4 I3=ā[(9 ā 1)/2]+3[3 ā1]+[(16 ā 9)/2]ā3[4ā3] I3=(ā 8)/2 +3[2]+ 7/2 ā 3[1] I3=ā4 +6+ 7/2 ā 3 I3=ā7 +6+ 7/2 I3=ā1+ 7/2 I3= (ā2 + 7)/2 I3= 5/2 Putting the values of I1 , I2 , I3 in (1) I=9/2 + 5/2 + 5/2 I = šš/š