InterviewSolution
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Which of the following statements are true and which are false? In each case give a valid reason for your answer.(i) p: √11 is an irrational number.(ii) q: Circle is a particular case of an ellipse.(iii) r: Each radius of a circle is a chord of the circle.(iv) S: The center of a circle bisects each chord of the circle.(v) t: If a and b are integers such that a < b, then –a > -b.(vi) y: The quadratic equation x2 + x + 1 = 0 has no real roots. |
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Answer» (i) p: √11 is an irrational number. True statement. Reason: An irrational number is any number which cannot be expressed as a fraction of two integers. √11 cannot be expressed as a fraction of two integers, so √11 is an irrational number. (ii) q: Circle is a particular case of an ellipse. True statement. Reason: The equation of an ellipse is x2/a2 + y2/b2 = 1 Special case: When a = b Then x2 + y2 = 1, which is an equation of circle. So, we can say that, a circle is a particular case of an ellipse with the same radius in all points. (iii) r: Each radius of a circle is a chord of the circle. False statement. Reason: A chord intersects the circle at two points, but radius intersects the circle only at one point. So the radius is not a chord of the circle. (iv) S: The center of a circle bisects each chord of the circle. False statement. Reason: The only diameter of a circle is bisected by the center of the circle. Except for diameter, no other chords are passes through the center of a circle. (v) t: If a and b are integers such that a < b, then –a > -b. True statement. Reason: a < b, then –a > - b [By rule of inequality] (vi) y: The quadratic equation x2 + x + 1 = 0 has no real roots. True statement. Reason: General form of a quadratic equation, ax2 + bx + c = 0, has no real roots if discriminant, D < 0. Where D= b2 – 4ac < 0. Given equation; x2 + x + 1 = 0 Here, a= 1, b = 1 and c = 1 Now, b2 – 4ac = 1 – 4 x 1 x 1 = -3 < 0 So, there is no real root. |
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