OhhAskMe
Login
Register
@
Dark Mode
Profile
Edit my Profile
Messages
My favorites
Register
All Activity
Q&A
Questions
Hot!
Unanswered
Users
Ask a Question
Dark Mode
For which x is the complex cosine function real?
TEBKariyer
asked
Jun 21, 2022
0
like
0
dislike
0
like
0
dislike
For which x is the complex cosine function real?
learnmath
TEBKariyer
asked
Jun 21, 2022
by
TEBKariyer
answer
comment
share this
share
0 Comments
Please
log in
or
register
to add a comment.
Please
log in
or
register
to answer this question.
2
Answers
0
like
0
dislike
0
like
0
dislike
If e^(ix) = a+ib then e^(-ix) = 1/e^(ix) = (a-ib)/(a^(2)+b^(2))
Show you need a^(2)+b^(2) = 1 or b = 0.
What does that imply about x?
ELLEDecoFR
answered
Jun 21, 2022
by
ELLEDecoFR
ask related question
comment
share this
0 Comments
Please
log in
or
register
to add a comment.
0
like
0
dislike
0
like
0
dislike
cos(a+bi) = cos(a)cosh(b) - i sin(a)sinh(b). you want the imaginary part to be 0, so you want sin(a) = 0 or sinh(b) = 0. so a = n pi or b = 0.
Yasminadotcom
answered
Jun 21, 2022
by
Yasminadotcom
ask related question
comment
share this
0 Comments
Please
log in
or
register
to add a comment.
No related questions found
33.4k
questions
135k
answers
0
comments
33.7k
users
OhhAskMe is a math solving hub where high school and university students ask and answer loads of math questions, discuss the latest in math, and share their knowledge. It’s 100% free!
Twitter
WhatsApp
Facebook
Reddit
LinkedIn
Email
Link Copied!
Copy