Code No: MA1501 R14
Model Question Paper
I B. Tech I Semester External Examinations
MATHEMATICS-I
(Common to All branches)
Time: 3 Hours Max. Marks: 60
Note: All Questions from Part A are to be answered at one place.
Answer any Four Questions from Part B
PART - A
6 X 2 = 12 M
1. Which integrating factor makes the non - exact differential equation (xy3 + y) dx + 2(x2
y2 + x + y4) dy = 0 to exact differential equation?
2. Solve (D2 – 2D + 4)2 y = 0
3. If x = eu cos v, y = eu sin v, find J = ( x, y )
(u , v )
4. Find the area between the parabolas y2 = 4ax and x2 = 4ay.
5. Find the directional derivative of f(x,y,z) = xy2 + yz3 at the point (2,-1,1) in the direction
of vector I + 2 J + 2K?
6. Find the work done by the force F (2 y 3)i xz j ( yz x)k when it moves a practical
from the point (0,0,0) to (2,1,1) along the curve x = 2t2 , y = t, z = t3.
PART- B
4 X 12 = 48 M
1. a) dy
Solve x y x3 y6 6M
dx
b) If 30% of radioactive substance disappeared in 10 days, how long will it take for 90%
of it to disappear? 6M
2. a) Solve (D2 -4D + 3) y = sin 3x cos2x 6M
b) Solve (D4 -1) y = ex cos x 6M
( x, y , z )
3. a) If u = xyz, v = x2 + y2 + z2 , w = x + y + z find 6M
(u, v, w)
b) A rectangular box open at the top is to have volume of 32 cubic ft. Find the
dimensions of the box requiring least material for its construction. 6M
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4. a) Trace the curve x3 + y3 = 3axy 6M
z dx dy dz , taken over the volume bounded by the surfaces x2 + y2 = a2, x2 + y2 =
2
b)
z and z = 0. 6M
5. a) Find the values of a and b such that the surfaces ax2 – byz = (a+2) x and 4x2 y + z3 = 4
cut orthogonally at (1,-1,2). 6M
b) Show that 2 r n n(n 1)r n2 6M
6. Verify Stok’s theorem for F ( x 2 y 2 )i 2 xy j taken around the rectangle bounded by
the lines x = a, y 0, y b. 12M
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