Applications of Derivatives

Choose the correct answer in: A cylindrical tank of radius 10 m is being filled with wheat at the rate of 314 cubic metre per hour. Then the depth of the wheat is increasing at the rate of (A) 1 m/h (B) 0.1 m/h (C) 1.1 m/h (D) 0.5 m/h

Equation of the curve is ……….(i)        Slope of the tangent to the given curve at point  =       ……….(ii) Now         …..(iii) Putting the values of  and  in eq. (i),      Therefore, The correct...

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Choose the correct answer in the questions :A cylindrical tank of radius 10 m is being filled with wheat at the rate of 314 cubic meter per hour. Then the depth of wheat is increasing at the rate of: (A) 1 m/h (B) 0.1 m/h (C) 1.1 m/h (D) 0.5 m/h

Let  be the depth of the wheat in the cylindrical tank of radius 10 m at time    V = Volume of wheat in cylindrical tank at time  cu. m It is given that  = 314 cu. m/hr         1 m/h Therefore,The...

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Show that height of the cylinder of greatest volume which can be inscribed in a right circular cone of height h and semi vertical angle α is one-third that of the cone and the greatest volume of cylinder is 4 /27πh^3tan^2 α .

 Let  be the radius of the right circular cone of height  Let the radius of the inscribed cylinder be  and height  In similar triangles APQ and ARC,          Volume of cylinder (V) = ……….(ii)  V = ...

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A tank with rectangular base and rectangular sides, open at the top is to be constructed so that its depth is 2 m and volume is 8 m^3 . If building of tank costs Rs 70 per sq metres for the base and Rs 45 per square metre for sides. What is the cost of least expensive tank?

Given: Depth of tank = 2 m Let  m be the length and  m be the breadth of the base of the tank. Volume of tank = 8 cubic meters       Cost of building the base of the tank at the rate of ` 70 per sq....

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Choose the correct answer The point on the curve x^ 2 = 2y which is nearest to the point (0, 5) is (A) (2 2,4) (B) (2 2,0) (C) (0, 0) (D) (2, 2)

Equation of the curve is                                                                                 ……….(i) Let P be any point on the curve (i), then according to question, Distance between...

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A wire of length 28 m is to be cut into two pieces. One of the pieces is to be made into a square and the other into a circle. What should be the length of the two pieces so that the combined area of the square and the circle is minimum?

 Let  meters be the side of square and  meters be the radius of the circle. Length of the wire = Perimeter of square + Circumference of circle    = 28      ……….(i) Area of square =  and Area of...

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A rectangular sheet of tin 45 cm by 24 cm is to be made into a box without top, by cutting off square from each corner and folding up the flaps. What should be the side of the square to be cut off so that the volume of the box is maximum ?

Dimensions of rectangular sheet are 45 cm and 24 cm. Let  cm be the side of each of the four squares cut off from each corner. Then dimensions of the open box formed by folding the flaps after...

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A square piece of tin of side 18 cm is to be made into a box without top, by cutting a square from each corner and folding up the flaps to form the box. What should be the side of the square to be cut off so that the volume of the box is the maximum possible.

Each side of square piece of tin is 18 cm. Let  cm be the side of each of the four squares cut off from each corner. Then dimensions of the open box formed by folding the flaps after cutting off...

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Find the absolute maximum value and the absolute minimum value of the following functions in the given intervals: (i) f(x) = x^ 3 , x ∈ [– 2, 2] (ii) f (x) = sin x + cos x , x ∈ [0, π]

 (i) Given:     Now      At   At   At   Therefore, absolute minimum value of  is  and absolute maximum value is 8. (ii) Given:     Now          [Positive]   is in I quadrant. [ ]       Therefore,...

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Find the local maxima and local minima, if any, of the following functions. Find also the local maximum and the local minimum values, as the case may be:(vii) g(x)=1/(x^2+2) (viii) f (x )=x√1- x , 0 <x<1

(vii) Given:       and =  Now      [Turning point] At    [Negative]    is a point of local maxima and local maximum value is  (viii) Given:      =  =  =  And  =  =  Now    = 0        is a point of...

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Find the local maxima and local minima, if any, of the following functions. Find also the local maximum and the local minimum values, as the case may be:(v) f(x) = x ^3 – 6x^ 2 + 9x + 15 (vi) x/2+2 /x , x>0

(v) Given:       and  Now          or    [Turning points] At   [Negative]    is a point of local maxima and local maximum value is  At     [Positive]    is a point of local minima and local minimum...

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Find the local maxima and local minima, if any, of the following functions. Find also the local maximum and the local minimum values, as the case may be: (iii) h(x) = sin x + cos x, 0 2 x π < < (iv) f(x) = sin x – cos x, 0 2 < < π

(iii) Given:         ……….(i)     and  Now            [Positive]    can have values in both I and III quadrant. But,  therefore,  is only in I quadrant.   =  [Turning point] At     = ...

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Find the local maxima and local minima, if any, of the following functions. Find also the local maximum and the local minimum values, as the case may be: (i) f(x) = x ^2 (ii) g(x) = x^ 3 – 3x

(i) Given:       and  Now        [Turning point] Again, when ,    [Positive] Therefore,  is a point of local minima and local minimum value =  (ii) Given:       and  Now           or  [Turning...

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Sand is pouring from a pipe at the rate of 12 cm3/s. The falling sand forms a cone on the ground in such a way that the height of the cone is always one-sixth of the radius of the base. How fast is the height of the sand cone increasing when the height is 4cm?

Let the height and radius of the sand-cone formed at time  second be  cm and  cm respectively. According to question,   Volume of cone (V) =  =  =    Now, since       ...

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A ladder 5 cm long is leaning against a wall. The bottom of the ladder is pulled along the ground, away from the wall, at the rate of 2 cm/s. How fast is its height on the wall decreasing when the foot of the ladder is 4 m away from the wall?

Let AB be the ladder and C is the junction of wall and ground, AB = 5 m  B Let CA =  meters, CB =  meters According to the equation,  increases,  decreases and  = 2 cm/s In AC2 + BC2 = AB2  [Using...

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