Maths

A telephone company in a town has 500 subscribers on its list and collects fixed charges of Rs 300/- per subscriber per year. The company proposes to increase the annual subscription and it is believed that for every increase of Rs 1/- one subscriber will discontinue the service. Find what increase will bring maximum profit?

We should consider that the organization expands the yearly membership by \[\mathbf{Rs}\text{ }\mathbf{x}.\] Along these lines, x is the quantity of supporters who end the administrations.  ...

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A swimming pool is to be drained for cleaning. If L represents the number of litres of water in the pool t seconds after the pool has been plugged off to drain and L = 200 (10 – t)2. How fast is the water running out at the end of 5 seconds? What is the average rate at which the water flows out during the first 5 seconds?

Given, \[L\text{ }=\text{ }200\left( 10\text{ }\text{ }t \right)2\] where L addresses the quantity of liters of water in the pool. On separating both the sides w.r.t, t, we get \[dL/dt\text{...

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A man, 2m tall, walks at the rate of m/s towards a street light which is m above the ground. At what rate is the tip of his shadow moving? At what rate is the length of the shadow changing when he is m from the base of the light?

Let AB is the stature of streetlamp post and CD is the tallness of the man with the end goal that \[AB\text{ }=\text{ }5\left( 1/3 \right)\text{ }=\text{ }16/3\text{ }m\text{ }and\text{ }CD\text{...

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Consider the non-empty set consisting of children in a family and a relation R defined as aRb if a is brother of b. Then R is (A) symmetric but not transitive (B) transitive but not symmetric (C) neither symmetric nor transitive (D) both symmetric and transitive

The correct option is (B) transitive but not symmetric Given aRb ⇒ a is brother of b. This does not mean b is also a brother of a as b can be a sister of a. Therefore, R is not symmetric. aRb ⇒ a is...

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Let T be the set of all triangles in the Euclidean plane, and let a relation R on T be defined as aRb if a is congruent to b ∀ a, b ∈ T. Then R is (A) reflexive but not transitive (B) transitive but not symmetric (C) equivalence (D) none of these

The correct option is (C) equivalence Given aRb, if a is congruent to b, ∀ a, b ∈ T. Then, we have aRa ⇒ a is congruent to a; which is always true. So, R is reflexive. Let aRb ⇒ a ~ b b ~ a bRa So,...

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Let * be binary operation defined on R by

    \[\mathbf{a}\text{ }*\text{ }\mathbf{b}\text{ }=\text{ }\mathbf{1}\text{ }+\text{ }\mathbf{ab},\forall \mathbf{a},\text{ }\mathbf{b}\in \mathbf{R}\]

. Then the operation * is (i) commutative but not associative (ii) associative but not commutative (iii) neither commutative nor associative (iv) both commutative and associative

(i) Given that * is a binary operation defined on R by \[\mathbf{a}\text{ }*\text{ }\mathbf{b}\text{ }=\text{ }\mathbf{1}\text{ }+\text{ }\mathbf{ab},\forall \mathbf{a},\text{ }\mathbf{b}\in...

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Each of the following defines a relation on N: (i) x is greater than y,

    \[\mathbf{x},\text{ }\mathbf{y}\in \mathbf{N}\]

(ii)

    \[\mathbf{x}\text{ }+\text{ }\mathbf{y}\text{ }=\text{ }\mathbf{10},\text{ }\mathbf{x},\text{ }\mathbf{y}\in \mathbf{N}\]

(iii) x y is square of an integer

    \[\mathbf{x},\text{ }\mathbf{y}\in \mathbf{N}\]

(iv)

    \[\mathbf{x}\text{ }+\text{ }\mathbf{4y}\text{ }=\text{ }\mathbf{10}\text{ }\mathbf{x},\text{ }\mathbf{y}\in \mathbf{N}\]

. Determine which of the above relations are reflexive, symmetric and transitive.

(i) Given, x is greater than y; \[\mathbf{x},\text{ }\mathbf{y}\in \mathbf{N}\] If \[\left( x,\text{ }x \right)\in R\], then \[x\text{ }>\text{ }x\], which is not true for any \[x\in N\]. Thus, R...

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A kite is moving horizontally at a height of 151.5 meters. If the speed of kite is 10 m/s, how fast is the string being let out; when the kite is 250 m away from the boy who is flying the kite? The height of boy is 1.5 m.

Speed of the kite(V) \[=\text{ }10\text{ }m/s\] Leave FD alone the tallness of the kite and AB be the stature of the kite and AB be the tallness of the kid. Presently, let AF \[=\text{ }x\text{ }m\]...

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