4) Evaluate , -dz, where y is the line from 1 → 1+ i

Algebra & Trigonometry with Analytic Geometry
13th Edition
ISBN:9781133382119
Author:Swokowski
Publisher:Swokowski
Chapter7: Analytic Trigonometry
Section7.6: The Inverse Trigonometric Functions
Problem 91E
icon
Related questions
icon
Concept explainers
Question
4) Evaluate - dz, where y is the line from 1 → 1+ i
Sy
'Y z
Transcribed Image Text:4) Evaluate - dz, where y is the line from 1 → 1+ i Sy 'Y z
Expert Solution
Step 1

In complex integration, we have to convert our given question into complex terms. But in our question lines is from 1 to 1+i and from these, we can say these curve does not contain the origin, so we can use antiderivative here without transforming into the complex form. 

The line is from 1 to 1+i, that is (1,0) to (1,1) in a complex plane. So it does not have (0,0), that's why I said above it does not contain origin so we can use antiderivative directly here.

Step 2

 We have   11+i1/z dz

11+i1/z dz =  logz11+i  = log (1+i) - log(1) = log(1+i)

We know log(1+i) = log2i*π/4.

Explanation for log(1+i):

x+iy = reiθ

x + iy = 1+i, so in our case x=1 and y =i.

r= (x2+y2) = (12+12) = 2

θ= tan-1y

In our case y =1, so θ=tan-11 = π/4  

 1+i =  2eiπ/4

log(1+i) = log(2eiπ/4) = log2+logeiπ/4 = log2 + iπ/4.  

 

The real part is log2 and the imaginary part is π/4

steps

Step by step

Solved in 3 steps

Blurred answer
Knowledge Booster
Points, Lines and Planes
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, algebra and related others by exploring similar questions and additional content below.
Recommended textbooks for you
Algebra & Trigonometry with Analytic Geometry
Algebra & Trigonometry with Analytic Geometry
Algebra
ISBN:
9781133382119
Author:
Swokowski
Publisher:
Cengage