**JNTU Mathematics Previous paper**

Code No: R05010102 Set No. 2

I B.Tech Regular Examinations, Apr/May 2007

MATHEMATICS-I

( Common to Civil Engineering, Electrical & Electronic Engineering,

Mechanical Engineering, Electronics & Communication Engineering,

Computer Science & Engineering, Chemical Engineering, Electronics &

Instrumentation Engineering, Bio-Medical Engineering, Information

Technology, Electronics & Control Engineering, Mechatronics, Computer

Science & Systems Engineering, Electronics & Telematics, Metallurgy &

Material Technology, Electronics & Computer Engineering, Production

Engineering, Aeronautical Engineering, Instrumentation & Control

Engineering and Automobile Engineering)

Time: 3 hours Max Marks: 80

Answer any FIVE Questions

All Questions carry equal marks

⋆ ⋆ ⋆ ⋆ ⋆

1. (a) Test the convergence of the following series P n2

2n + 1

n2 [5]

(b) Find the interval of convergence of the series whose n th term is P (−1)n(n+2)

(2n +5)

[5]

(c) If a < b prove that b−a (1+b2) < tan−1b − tan−1a < b−a (1+a2) using Lagrange’s Mean value theorem. Deduce the following [6] i. 4 + 3 25 < tan−1 4 3 < 4 + 1 6 ii. 5 +4 20 < tan−1 2 < +2 4 2. (a) If u=x2-y2, v=2xy where x=r cosθ, y=rsinθ. Show that @(u,v) @(r, ) = 4r3. (b) For the cardioid r=a(1+cosθ) Prove that 2 r is constant where rho is the radius of curvature. [8+8] 3. (a) Find the volume of the solid generated by revolution of y2 = x3 (2a−x) about its asymptote. (b) Find the area of the loop of the curve r=a(1+cos θ). [8+8] 4. (a) Form the differential equation by eliminating the arbitrary constant y = a+x x2+1 . [3] (b) Solve the differential equation: (1-x 2) dy dx - xy = y3sin −1x. [7] (c) Prove that the family of confocal conics x2 a2+ + y2 b2+ = 1 are self orthogonal (λ the parameter) [6] 5. (a) Solve the differential equation: (D3 − 7D2 + 14D − 8)y = excos2x. (b) Solve the differential equation: (x2D2 − x3D + 1)y = log x sin (log x)+1 x . [8+8] 6. (a) Solve the differential equation d2x dx2 + 9x = Sin t using Laplace transforms given that x(0) = 1, x(π/2) =1 1 of 2 Code No: R05010102 Set No. 2 (b) Change the order of integration hence evaluate 1 R0 2−x Rx2 xdy dx [8+8] 7. (a) Prove that ∇x(∇xA) = -∇2A+∇(∇.A). (b) If φ = 2xy2z +x2y, evaluate RC φ dr where C consists of the straight lines from (0, 0, 0) to (1, 0, 0) then to (1, 1, 0) and then to (1, 1, 1). [8+8] 8. Verify Green’s theorem for HC (y − Sin x ) dx + Cos x dy where C is the triangle formed by the points (0,0) (π/2, 0) and (π/2, 1). [16] Download the previous paper in Pdf format click here