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Let A ( 3 a , a ) , a > 0 , be a fixed point in the xy-plane. The image of A in y-axis be B and the image of B in x-axis be C. If D (3 cos q, a sin q) is a point in the fourth quadrant such that the maximum area of Δ A C D is 12 square units, then a is equal to _________.

0 5 Views | Posted 2 months ago
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  • A

    Answered by

    alok kumar singh | Contributor-Level 10

    2 months ago

    B ( − 3 a , a ) a n d     c ( − 3 a , − a )

    ∴ A r e a     o f     Δ A C D = 1 2 | 3 a a 1 − 3 a − a 1 3 c o s θ a s i n θ 1 |  = 12 

    ⇒ Δ = 3 a | c o s θ + s i n θ | = 1 2

    ∴ Δ m a x = 3 a . 2 = 1 2 ⇒ a = 8

                   

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Option (B) is correct

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alok kumar singh

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The line passes through the centre of circle x2 + y2 – 16x – 4y = 0, it interacts with the positive coordinate axis at A & B. Then find the minimum value of OA + OB, where O is origin.
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alok kumar singh

(y – 2) = m (x – 8)

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Kindly consider the following figure

A man is walking on a straight line. The arithmetic mean of the reciprocals of the intercepts of the line on the coordinate axes is 1 4 .  Three stones A, B and C are placed at the point (1, 1), (2, 2) and (4, 4) respectively. Then which of these stones is / are on the path of the man?
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According to question,

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