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Class 11 Set Exercise 1.3 Solutions

13. Make correct statements by filling in the symbols $\subset$ or ? in the blank spaces :

(i) { 2, 3, 4 } . . . { 1, 2, 3, 4,5 }

(ii) { a, b, c } . . . { b, c, d }

(iii) {x : x is a student of Class XI of your school}. . .{x : x student of your school}

(iv) {x : x is a circle in the plane} . . .{x : x is a circle in the same plane with radius 1 unit}

(v) {x : x is a triangle in a plane} . . . {x : x is a rectangle in the plane}

(vi) {x : x is an equilateral triangle in a plane} . . . {x : x is a triangle in the same plane}

(vii) {x : x is an even natural number} . . . {x : x is an integer}

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Payal Gupta | Contributor-Level 10

3 months ago

13. (i) {2,3,4} $\subset$ {1,2,3,4,5}

(ii) {a, b, c} ? {b, c, d}

(iii) {x : x is a student of class XI of yours school} $\subset$ {x : x is a student of your school}

(iv) As any circle in the plane can have radius more or less than 1 unit.

(x : x is a circle in the plane) ? {x : x is a circle in the same plane with radius 1 unit}

(v) As a triangle can never be a rectangle.

{x : x is a triangle in a plane} ? {x : x is a triangle in the same plane}

(vi) Any triangle in a plane can be scaler, isosceles, equilateral.

So. {x : x is a equilateral triangle in a plane} $\subset$ {x : x is a triangle in the same plane}

(vii) As all eve

...more

13. (i) {2,3,4} $\subset$ {1,2,3,4,5}

(ii) {a, b, c} ? {b, c, d}

(iii) {x : x is a student of class XI of yours school} $\subset$ {x : x is a student of your school}

(iv) As any circle in the plane can have radius more or less than 1 unit.

(x : x is a circle in the plane) ? {x : x is a circle in the same plane with radius 1 unit}

(v) As a triangle can never be a rectangle.

{x : x is a triangle in a plane} ? {x : x is a triangle in the same plane}

(vi) Any triangle in a plane can be scaler, isosceles, equilateral.

So. {x : x is a equilateral triangle in a plane} $\subset$ {x : x is a triangle in the same plane}

(vii) As all even natural number is also an integer.

{x : x is an even natural number} $\subset$ {x : x is an integer}.

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The number of elements in the set {x ∈ R : (|x| - 3)|x + 4| = 6} is equal to :

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(|x| - 3)|x + 4| = 6

Case (i) x < -4
(-x - 3) (- (x + 4) = 6
(x + 3) (x + 4) = 6 ⇒ x² + 7x + 12 = 6 ⇒ x² + 7x + 6 = 0
(x + 1) (x + 6) = 0 ⇒ x = -6 (since x < -4)

Case (ii) -4 ≤ x < 0
(-x - 3) (x + 4) = 6
⇒ -x² - 7x - 12 = 6
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66. Given series is 1× 2× 3 + 2× 3 ×4 + 3× 4 ×5 + … to n term

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Class 11 Set Exercise 1.3 Solutions

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