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Page 1 JEE Solved Example on Application of Integral JEE Mains Q1: The area bounded by the ?? -axis, the curve ?? = ?? ( ?? ) and the lines ?? = ?? , ?? = ?? is equal to v?? ?? + ?? - v ?? for all ?? > ?? , then ?? ( ?? ) is (a) v ?? - ?? (b) v ?? + ?? (c) v ?? ?? - ?? (d) ?? v ?? +?? ?? Ans: (d) ? 1 ?? ??? ( ?? ) ???? = v ?? 2 + 1 - v 2 = [v ?? 2 + 1] 1 ?? ? ?? ( ?? ) = 1 2 · 2?? v?? 2 + 1 Hence ?? ( ?? ) = ?? v1+?? 2 . Q2: The area of the region bounded by the curve ?? = ?? - ?? ?? between ?? = ?? and ?? = ?? is (a) ?? ?? (b) ?? ?? (c) ?? ?? (d) ?? ?? Ans: (a) Required Area = ? 0 1 ?( ?? - ?? 2 ) ???? = [ ?? 2 2 - ?? 3 3 ] 0 1 = 1 2 - 1 3 = 1 6 . Q3: Find the area bounded between the curve ?? ?? = ?? ?? - ?? and ?? -axis . (a) ?? ?? (b) ?? ?? (c) ?? ?? (d) 5 Ans: (a) The area between the given curve ?? = 2?? - ?? 2 and ?? -axis will be as shown Page 2 JEE Solved Example on Application of Integral JEE Mains Q1: The area bounded by the ?? -axis, the curve ?? = ?? ( ?? ) and the lines ?? = ?? , ?? = ?? is equal to v?? ?? + ?? - v ?? for all ?? > ?? , then ?? ( ?? ) is (a) v ?? - ?? (b) v ?? + ?? (c) v ?? ?? - ?? (d) ?? v ?? +?? ?? Ans: (d) ? 1 ?? ??? ( ?? ) ???? = v ?? 2 + 1 - v 2 = [v ?? 2 + 1] 1 ?? ? ?? ( ?? ) = 1 2 · 2?? v?? 2 + 1 Hence ?? ( ?? ) = ?? v1+?? 2 . Q2: The area of the region bounded by the curve ?? = ?? - ?? ?? between ?? = ?? and ?? = ?? is (a) ?? ?? (b) ?? ?? (c) ?? ?? (d) ?? ?? Ans: (a) Required Area = ? 0 1 ?( ?? - ?? 2 ) ???? = [ ?? 2 2 - ?? 3 3 ] 0 1 = 1 2 - 1 3 = 1 6 . Q3: Find the area bounded between the curve ?? ?? = ?? ?? - ?? and ?? -axis . (a) ?? ?? (b) ?? ?? (c) ?? ?? (d) 5 Ans: (a) The area between the given curve ?? = 2?? - ?? 2 and ?? -axis will be as shown ? Required Area = ? ? 2 0 ?( 2?? - ?? 2 ) ???? = [?? 2 - ?? 3 3 ] 0 2 = 4 3 Q4: Find the area bounded by the curves ?? = ?? ?????? ?? , ?? = ?? ?????? ?? in the first quadrant (a) ?????? ?? (b) ?? ?? ?? ?? ?? (c) ???? ?? ?? ?? (d) None of these Ans: (a) Clearly the given equation are the parametric equation of ellipse ?? 2 ?? 2 + ?? 2 ?? 2 = 1. Curve meet the ?? -axis in the first quadrant at ( ?? , ?? ) ? Required area ? 0 ?? ??????? = ? ?? 2 0 ?( ?? sin ?? ) ( -?? cos ?? ) ???? = ???? ? 0 ?? /2 ?sin 2 ?????? = ( ?????? 4 ) ( ? At ?? = 0, ?? = ?? /2 and ?? = ?? , ?? = 0) Q5: Find the whole area of circle ?? ?? + ?? ?? = ?? ?? (a) ?? (b) ?? ?? ?? (c) ?? ?? ?? (d) ?? ?? Ans: (b) The required area is symmetric about both the axis as shown in figure Page 3 JEE Solved Example on Application of Integral JEE Mains Q1: The area bounded by the ?? -axis, the curve ?? = ?? ( ?? ) and the lines ?? = ?? , ?? = ?? is equal to v?? ?? + ?? - v ?? for all ?? > ?? , then ?? ( ?? ) is (a) v ?? - ?? (b) v ?? + ?? (c) v ?? ?? - ?? (d) ?? v ?? +?? ?? Ans: (d) ? 1 ?? ??? ( ?? ) ???? = v ?? 2 + 1 - v 2 = [v ?? 2 + 1] 1 ?? ? ?? ( ?? ) = 1 2 · 2?? v?? 2 + 1 Hence ?? ( ?? ) = ?? v1+?? 2 . Q2: The area of the region bounded by the curve ?? = ?? - ?? ?? between ?? = ?? and ?? = ?? is (a) ?? ?? (b) ?? ?? (c) ?? ?? (d) ?? ?? Ans: (a) Required Area = ? 0 1 ?( ?? - ?? 2 ) ???? = [ ?? 2 2 - ?? 3 3 ] 0 1 = 1 2 - 1 3 = 1 6 . Q3: Find the area bounded between the curve ?? ?? = ?? ?? - ?? and ?? -axis . (a) ?? ?? (b) ?? ?? (c) ?? ?? (d) 5 Ans: (a) The area between the given curve ?? = 2?? - ?? 2 and ?? -axis will be as shown ? Required Area = ? ? 2 0 ?( 2?? - ?? 2 ) ???? = [?? 2 - ?? 3 3 ] 0 2 = 4 3 Q4: Find the area bounded by the curves ?? = ?? ?????? ?? , ?? = ?? ?????? ?? in the first quadrant (a) ?????? ?? (b) ?? ?? ?? ?? ?? (c) ???? ?? ?? ?? (d) None of these Ans: (a) Clearly the given equation are the parametric equation of ellipse ?? 2 ?? 2 + ?? 2 ?? 2 = 1. Curve meet the ?? -axis in the first quadrant at ( ?? , ?? ) ? Required area ? 0 ?? ??????? = ? ?? 2 0 ?( ?? sin ?? ) ( -?? cos ?? ) ???? = ???? ? 0 ?? /2 ?sin 2 ?????? = ( ?????? 4 ) ( ? At ?? = 0, ?? = ?? /2 and ?? = ?? , ?? = 0) Q5: Find the whole area of circle ?? ?? + ?? ?? = ?? ?? (a) ?? (b) ?? ?? ?? (c) ?? ?? ?? (d) ?? ?? Ans: (b) The required area is symmetric about both the axis as shown in figure ? Required area = 4 ? ? ?? 0 ? v?? 2 - ?? 2 ???? = 4 [ ?? 2 v?? 2 - ?? 2 + ?? 2 2 sin -1 ?? ?? ] 0 ?? = 4 [ ?? 2 × ?? 2 2 ] = ?? ?? 2 Q6: Find the area bounded by the parabola ?? ?? = ?? ?? and its latus rectum [ (a) ?? ?? (b) ?? ?? (c) ???? ?? (d) None of these Ans: (a) Since the curve is symmetrical about ?? -axis, therefore the required area = 2 ? ? 1 0 ??????? = 2 ? ? 1 0 ?v 4?? ???? = 4 · 2 3 [?? 3 2 ] 0 1 = 8 3 Page 4 JEE Solved Example on Application of Integral JEE Mains Q1: The area bounded by the ?? -axis, the curve ?? = ?? ( ?? ) and the lines ?? = ?? , ?? = ?? is equal to v?? ?? + ?? - v ?? for all ?? > ?? , then ?? ( ?? ) is (a) v ?? - ?? (b) v ?? + ?? (c) v ?? ?? - ?? (d) ?? v ?? +?? ?? Ans: (d) ? 1 ?? ??? ( ?? ) ???? = v ?? 2 + 1 - v 2 = [v ?? 2 + 1] 1 ?? ? ?? ( ?? ) = 1 2 · 2?? v?? 2 + 1 Hence ?? ( ?? ) = ?? v1+?? 2 . Q2: The area of the region bounded by the curve ?? = ?? - ?? ?? between ?? = ?? and ?? = ?? is (a) ?? ?? (b) ?? ?? (c) ?? ?? (d) ?? ?? Ans: (a) Required Area = ? 0 1 ?( ?? - ?? 2 ) ???? = [ ?? 2 2 - ?? 3 3 ] 0 1 = 1 2 - 1 3 = 1 6 . Q3: Find the area bounded between the curve ?? ?? = ?? ?? - ?? and ?? -axis . (a) ?? ?? (b) ?? ?? (c) ?? ?? (d) 5 Ans: (a) The area between the given curve ?? = 2?? - ?? 2 and ?? -axis will be as shown ? Required Area = ? ? 2 0 ?( 2?? - ?? 2 ) ???? = [?? 2 - ?? 3 3 ] 0 2 = 4 3 Q4: Find the area bounded by the curves ?? = ?? ?????? ?? , ?? = ?? ?????? ?? in the first quadrant (a) ?????? ?? (b) ?? ?? ?? ?? ?? (c) ???? ?? ?? ?? (d) None of these Ans: (a) Clearly the given equation are the parametric equation of ellipse ?? 2 ?? 2 + ?? 2 ?? 2 = 1. Curve meet the ?? -axis in the first quadrant at ( ?? , ?? ) ? Required area ? 0 ?? ??????? = ? ?? 2 0 ?( ?? sin ?? ) ( -?? cos ?? ) ???? = ???? ? 0 ?? /2 ?sin 2 ?????? = ( ?????? 4 ) ( ? At ?? = 0, ?? = ?? /2 and ?? = ?? , ?? = 0) Q5: Find the whole area of circle ?? ?? + ?? ?? = ?? ?? (a) ?? (b) ?? ?? ?? (c) ?? ?? ?? (d) ?? ?? Ans: (b) The required area is symmetric about both the axis as shown in figure ? Required area = 4 ? ? ?? 0 ? v?? 2 - ?? 2 ???? = 4 [ ?? 2 v?? 2 - ?? 2 + ?? 2 2 sin -1 ?? ?? ] 0 ?? = 4 [ ?? 2 × ?? 2 2 ] = ?? ?? 2 Q6: Find the area bounded by the parabola ?? ?? = ?? ?? and its latus rectum [ (a) ?? ?? (b) ?? ?? (c) ???? ?? (d) None of these Ans: (a) Since the curve is symmetrical about ?? -axis, therefore the required area = 2 ? ? 1 0 ??????? = 2 ? ? 1 0 ?v 4?? ???? = 4 · 2 3 [?? 3 2 ] 0 1 = 8 3 Q7: The area bounded by the curve ?? ?? = ?? ?? and ?? ?? = ?? ?? is (a) ???? ?? sq. units (b) ?? ???? sq. units (c) ???? ?? sq. units (d) ?? ???? sq. units Ans: (a) Required area = ? 0 4 ?( ???????? - ???????? ) Region = ? 0 4 ?(v 4?? - ?? 2 4 )???? = 16 3 square unit. Trick : From Important Tips' the area of the region bounded by ?? 2 = 4???? and ?? 2 = 4???? is 16???? 3 square unit. Here ?? 2 = 4?? and ?? 2 = 4?? , so ?? = 1 and ?? = 1 Required area = 16 3 ( 1) ( 1) = 16 3 square unit. Q8: The area of the bounded region by the curve ?? = ?????? ?? , the ?? -axis and the line ?? = ?? and ?? = ?? is (a) 4 (b) 2 (c) ?? (d) None of these Ans: (b) Required area = ? ? ?? 0 ?sin ?????? = 2 ? ? ?? /2 0 ?sin ?????? = 2[-cos ?? ] 0 ?? /2 = 2[( -cos ?? /2)- ( -cos 0) ] = 2( 1) = 2 square unit. Page 5 JEE Solved Example on Application of Integral JEE Mains Q1: The area bounded by the ?? -axis, the curve ?? = ?? ( ?? ) and the lines ?? = ?? , ?? = ?? is equal to v?? ?? + ?? - v ?? for all ?? > ?? , then ?? ( ?? ) is (a) v ?? - ?? (b) v ?? + ?? (c) v ?? ?? - ?? (d) ?? v ?? +?? ?? Ans: (d) ? 1 ?? ??? ( ?? ) ???? = v ?? 2 + 1 - v 2 = [v ?? 2 + 1] 1 ?? ? ?? ( ?? ) = 1 2 · 2?? v?? 2 + 1 Hence ?? ( ?? ) = ?? v1+?? 2 . Q2: The area of the region bounded by the curve ?? = ?? - ?? ?? between ?? = ?? and ?? = ?? is (a) ?? ?? (b) ?? ?? (c) ?? ?? (d) ?? ?? Ans: (a) Required Area = ? 0 1 ?( ?? - ?? 2 ) ???? = [ ?? 2 2 - ?? 3 3 ] 0 1 = 1 2 - 1 3 = 1 6 . Q3: Find the area bounded between the curve ?? ?? = ?? ?? - ?? and ?? -axis . (a) ?? ?? (b) ?? ?? (c) ?? ?? (d) 5 Ans: (a) The area between the given curve ?? = 2?? - ?? 2 and ?? -axis will be as shown ? Required Area = ? ? 2 0 ?( 2?? - ?? 2 ) ???? = [?? 2 - ?? 3 3 ] 0 2 = 4 3 Q4: Find the area bounded by the curves ?? = ?? ?????? ?? , ?? = ?? ?????? ?? in the first quadrant (a) ?????? ?? (b) ?? ?? ?? ?? ?? (c) ???? ?? ?? ?? (d) None of these Ans: (a) Clearly the given equation are the parametric equation of ellipse ?? 2 ?? 2 + ?? 2 ?? 2 = 1. Curve meet the ?? -axis in the first quadrant at ( ?? , ?? ) ? Required area ? 0 ?? ??????? = ? ?? 2 0 ?( ?? sin ?? ) ( -?? cos ?? ) ???? = ???? ? 0 ?? /2 ?sin 2 ?????? = ( ?????? 4 ) ( ? At ?? = 0, ?? = ?? /2 and ?? = ?? , ?? = 0) Q5: Find the whole area of circle ?? ?? + ?? ?? = ?? ?? (a) ?? (b) ?? ?? ?? (c) ?? ?? ?? (d) ?? ?? Ans: (b) The required area is symmetric about both the axis as shown in figure ? Required area = 4 ? ? ?? 0 ? v?? 2 - ?? 2 ???? = 4 [ ?? 2 v?? 2 - ?? 2 + ?? 2 2 sin -1 ?? ?? ] 0 ?? = 4 [ ?? 2 × ?? 2 2 ] = ?? ?? 2 Q6: Find the area bounded by the parabola ?? ?? = ?? ?? and its latus rectum [ (a) ?? ?? (b) ?? ?? (c) ???? ?? (d) None of these Ans: (a) Since the curve is symmetrical about ?? -axis, therefore the required area = 2 ? ? 1 0 ??????? = 2 ? ? 1 0 ?v 4?? ???? = 4 · 2 3 [?? 3 2 ] 0 1 = 8 3 Q7: The area bounded by the curve ?? ?? = ?? ?? and ?? ?? = ?? ?? is (a) ???? ?? sq. units (b) ?? ???? sq. units (c) ???? ?? sq. units (d) ?? ???? sq. units Ans: (a) Required area = ? 0 4 ?( ???????? - ???????? ) Region = ? 0 4 ?(v 4?? - ?? 2 4 )???? = 16 3 square unit. Trick : From Important Tips' the area of the region bounded by ?? 2 = 4???? and ?? 2 = 4???? is 16???? 3 square unit. Here ?? 2 = 4?? and ?? 2 = 4?? , so ?? = 1 and ?? = 1 Required area = 16 3 ( 1) ( 1) = 16 3 square unit. Q8: The area of the bounded region by the curve ?? = ?????? ?? , the ?? -axis and the line ?? = ?? and ?? = ?? is (a) 4 (b) 2 (c) ?? (d) None of these Ans: (b) Required area = ? ? ?? 0 ?sin ?????? = 2 ? ? ?? /2 0 ?sin ?????? = 2[-cos ?? ] 0 ?? /2 = 2[( -cos ?? /2)- ( -cos 0) ] = 2( 1) = 2 square unit. Trick : For the curve ?? = sin ?? or cos ?? , the area of ? 0 ?? /2 ?sin ?????? = 1, ? 0 ?? ?sin ?????? = 2, ? 0 3?? /2 ?sin ?????? = 3, ? 0 2?? ?sin ?????? = 4 and so on. Q9: The area enclosed by the parabola ?? ?? = ?? ?? and the line ?? = ?? ?? is (a) ?? ?? (b) ?? ?? (c) ?? ?? (d) ?? ?? Ans: (a) Solve the equation ?? 2 = 8?? and the line ?? = 2?? , we get the point of intersection. Then find the required area bounded by this region. It is 4 3 . Trick : Required area = 8( 2) 2 3( 2) 3 = 32 24 = 4 3 [? Area bounded by ?? 2 = 4???? and ?? = ???? is 8?? 2 3?? 3 . Here ?? = 2, ?? = 2] Q10: If the area bounded by ?? = ?? ?? ?? and ?? = ?? ?? ?? , ?? > ?? , is 1 , then ?? = (a) 1 (b) ?? v ?? (c) ?? ?? (d) - ?? v ?? Ans: (b) The ?? coordinate of A is 1 ?? According to the given conditionRead More
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3. How are integrals helpful in determining the work done by a force? |
4. Can integrals be used to find the volume of irregular shapes or solids? |
5. In what ways can integrals be utilized in analyzing population growth or decay? |
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