Civil Engineering (CE) Exam  >  Civil Engineering (CE) Questions  >  The real part of an analytic function f(z) wh... Start Learning for Free
The real part of an analytic function f(z) where z = x + iy is given by e-y cos (x). The imaginary part of f(z) is
  • a)
    ey cos (x)
  • b)
    e-y sin (x)
  • c)
    -ey sin (x)
  • d)
    -e-y sin (x)
Correct answer is option 'B'. Can you explain this answer?
Most Upvoted Answer
The real part of an analytic function f(z) where z = x + iy is given b...
The real part of an analytic function f(z) is given by e^(-y) * cos(x). We are required to find the imaginary part of f(z).

To find the imaginary part of f(z), we can make use of the Cauchy-Riemann equations. According to these equations, if f(z) is an analytic function, then it satisfies the following conditions:

∂u/∂x = ∂v/∂y (1)
∂u/∂y = -∂v/∂x (2)

where u(x, y) is the real part of f(z) and v(x, y) is the imaginary part of f(z).

Let's differentiate the given real part of f(z) with respect to x and y:

∂u/∂x = -e^(-y) * sin(x) (3)
∂u/∂y = -e^(-y) * cos(x) (4)

Comparing equations (1) and (3), we can see that:

∂v/∂y = -e^(-y) * sin(x) (5)

Comparing equations (2) and (4), we can see that:

∂v/∂x = e^(-y) * cos(x) (6)

Now, integrating equation (5) with respect to y, we get:

v(x, y) = -e^(-y) * sin(x) + g(x) (7)

where g(x) is an arbitrary function of x.

Next, substituting equation (7) into equation (6), we can solve for g(x):

∂v/∂x = e^(-y) * cos(x) (6)
e^(-y) * cos(x) = e^(-y) * cos(x) + g'(x) (8)
g'(x) = 0 (9)

Since g'(x) = 0, it implies that g(x) is a constant.

Therefore, the imaginary part of f(z) is given by:

v(x, y) = -e^(-y) * sin(x) + C (10)

where C is a constant.

Comparing equation (10) with the given options, we can see that the correct answer is option B, i.e., e^(-y) * sin(x).
Free Test
Community Answer
The real part of an analytic function f(z) where z = x + iy is given b...
Concept:
If f(z) = u + iv is an analytic function, then it satisfies the following:
Calculation:
Given: u = e-y cos x
∂u/∂x = −e−y sin⁡x
∂u/∂y = −e−y cos⁡x
∂v/∂y = −e−y sin⁡x    ---(1)
∂v/∂x = e−y cos⁡x      ---(2)
Integrate equation (1) w.r.t. y, taking x as constant, we get:
v = e-y sin x
Explore Courses for Civil Engineering (CE) exam

Top Courses for Civil Engineering (CE)

The real part of an analytic function f(z) where z = x + iy is given by e-y cos (x). The imaginary part of f(z) isa)ey cos (x)b)e-y sin (x)c)-ey sin (x)d)-e-y sin (x)Correct answer is option 'B'. Can you explain this answer?
Question Description
The real part of an analytic function f(z) where z = x + iy is given by e-y cos (x). The imaginary part of f(z) isa)ey cos (x)b)e-y sin (x)c)-ey sin (x)d)-e-y sin (x)Correct answer is option 'B'. Can you explain this answer? for Civil Engineering (CE) 2024 is part of Civil Engineering (CE) preparation. The Question and answers have been prepared according to the Civil Engineering (CE) exam syllabus. Information about The real part of an analytic function f(z) where z = x + iy is given by e-y cos (x). The imaginary part of f(z) isa)ey cos (x)b)e-y sin (x)c)-ey sin (x)d)-e-y sin (x)Correct answer is option 'B'. Can you explain this answer? covers all topics & solutions for Civil Engineering (CE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for The real part of an analytic function f(z) where z = x + iy is given by e-y cos (x). The imaginary part of f(z) isa)ey cos (x)b)e-y sin (x)c)-ey sin (x)d)-e-y sin (x)Correct answer is option 'B'. Can you explain this answer?.
Solutions for The real part of an analytic function f(z) where z = x + iy is given by e-y cos (x). The imaginary part of f(z) isa)ey cos (x)b)e-y sin (x)c)-ey sin (x)d)-e-y sin (x)Correct answer is option 'B'. Can you explain this answer? in English & in Hindi are available as part of our courses for Civil Engineering (CE). Download more important topics, notes, lectures and mock test series for Civil Engineering (CE) Exam by signing up for free.
Here you can find the meaning of The real part of an analytic function f(z) where z = x + iy is given by e-y cos (x). The imaginary part of f(z) isa)ey cos (x)b)e-y sin (x)c)-ey sin (x)d)-e-y sin (x)Correct answer is option 'B'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of The real part of an analytic function f(z) where z = x + iy is given by e-y cos (x). The imaginary part of f(z) isa)ey cos (x)b)e-y sin (x)c)-ey sin (x)d)-e-y sin (x)Correct answer is option 'B'. Can you explain this answer?, a detailed solution for The real part of an analytic function f(z) where z = x + iy is given by e-y cos (x). The imaginary part of f(z) isa)ey cos (x)b)e-y sin (x)c)-ey sin (x)d)-e-y sin (x)Correct answer is option 'B'. Can you explain this answer? has been provided alongside types of The real part of an analytic function f(z) where z = x + iy is given by e-y cos (x). The imaginary part of f(z) isa)ey cos (x)b)e-y sin (x)c)-ey sin (x)d)-e-y sin (x)Correct answer is option 'B'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice The real part of an analytic function f(z) where z = x + iy is given by e-y cos (x). The imaginary part of f(z) isa)ey cos (x)b)e-y sin (x)c)-ey sin (x)d)-e-y sin (x)Correct answer is option 'B'. Can you explain this answer? tests, examples and also practice Civil Engineering (CE) tests.
Explore Courses for Civil Engineering (CE) exam

Top Courses for Civil Engineering (CE)

Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev