Anna University Coimbatore 2009 B.E 2 ks with Answer for Transforms and Partial Differential Equations ( Unit-3 PDE) - Question Paper
TRANSFORMS AND PARTIAL DIFFERENTIAL EQUATIONS
ANNA UNIVERSITY (2 Marks) QUESTIONS WITH ANSWERS
UNIT III
PARTIAL DIFFERENTIAL EQUATIONS
TWO MARKS
1) Solve .
Solution:
2) Find the complete integral of .
Solution:
Given,
This is of the form
Hence the Complete integral is
3) Form the PDE by eliminating the arbitrary constants a and b from the equation .
Solution:
4) Find the complete solution of the PDE .
Solution:
Given,
The complete integral is
Hence
Therefore,The complete solution is
5) Form the PDE of all spheres whose centers lie on the z-axis.
Solution:
The equation of such spheres with centre (0,0,c) and radius r is
where r, c are constants.
Differentiating p. w.r.to x and y , we get
Substituting (3) in (2), we get
6) Find complete integral of the PDE .
Solution:
Given,
This is of the form .
The Auxillary equation is
Now Consider
Integrating this we get
Now Consider
Integrating this we get
Hence, The General Solution is
7) Obtain the PDE by eliminating the arbitrary constants a and b from the equation .
Solution:
,
Similarly,
8) Find the general solution of .
Solution:
The Auxillary equation is
9) Eliminate the arbitrary function f from and form the PDE.
Solution:
Differentiating the given equation p.w.r.to and ,
Divide by .
10) Find the Complete integral of .
Solution:
Given
This is of the form
Solution is subject to
. This is the C.I. of
11) Find the PDE of all planes passing through the origin.
Solution:
The general equation to a plane is
where a, b, c, d are constants.
Since passes through
Substitute the values of a & b in
.
12) Find the particular integral of .
Solution:
13) Find the solution of .
Solution:
Given,
This is of the form .
The Auxillary equation is
Now Consider
Integrating this we get
Now Consider
Integrating this we get
Hence, The General Solution is
14) Solve .
Solution:
satisfies this equation , also satisfies this equation and
The roots are
Solution is where are arbitrary functions of .
15) Solve .
Solution:
Solution is where are arbitrary functions of .
16) Form the PDE by eliminating the arbitrary constants a and b from . Solution:
Differentiating the given equation p.w.r.to and ,
Substituting & in ,
.
17) Solve
Solution:
The given equation can be written as
The complete solution is .
18) Solve
Solution:
.
Solution is .
19) Form the PDE by eliminating the arbitrary function from .
Solution:
Differentiating p.w.r.to in turn,
Equating & we get
20) Write down the complete solution of .
Solution:
The given PDE is Clairauts Form
The complete solution is got by putting in the given PDE.
The C.I. is where and are arbitrary constants.
21) Find the singular solution of .
Solution:
This is Clairauts Form. Hence the complete integral is
Differentiating partially w.r.to and respectively we get
and
Substituting in we get
.
22) Find the general solution of .
Solution:
Given,
This is of the form .
The Auxillary equation is
Now Consider
Integrating this we get
Now Consider
Integrating this we get
Hence, The General Solution is .
23) Find the particular integral of .
Solution:
Hence
24) Solve
Solution:
The given equation is of the
The complete integral is where
Now
The complete integral is .
.
25) Form the p.d.e by eliminating a and b from .
Solution:
Given
Differentiating the above equation p.w.r.to and ,
From & we get,
26) Solve .
Solution:
Given, . This is of the form
Let
Substitute these values in
.
27) Give the general solution of .
Solution:
Given,
Integrating with respect to , we get
Again Integrating with respect to ,
. Hereandare arbitrary functions of and respectively.
28) Solve .
Solution:
Here
The solution is
29) Form the partial differential equation by eliminating from the relation .
Solution:
Given,
Differentiating p.w.r.to we get
Differentiating p.w.r.to we get
From & we get, . .
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