# Help with My complex functions

1. May 9, 2010

### json078

Help with My complex functions :(

1. The problem statement, all variables and given/known data
I have to find a real part and Imaginary part of complex functions
but I kinda stuck on this question :(

2. Relevant equations
f(t)=e(-1+2i)(2-i ; 3+4i)

from this equation I have to find real part and imaginary part :(
I need ur help guyz asap
!!!!:) cheers

3. The attempt at a solution

2. May 9, 2010

### Staff: Mentor

Re: Help with My complex functions :(

There seems to be something missing in your function. The expression on the right side doesn't have t in it. Is this the formula for your function?
f(t) = e(-1 + 2i)t(2 - i; 3 + 4i)

3. May 9, 2010

### json078

Re: Help with My complex functions :(

true that
the original function is
f(t) = e(-1+2i)t[2-i ; 3+4i]

4. May 10, 2010

### HallsofIvy

Re: Help with My complex functions :(

What you have written makes no sense. What is that "e" doing in your formula? Do you really mean it to just be multiplied or do you intend e^{(-1+ 2i)t}? And what is "[2-i ; 3+4i]" is this a "vector valued" function? And, if so, do you want the real and imaginary parts of each component?

5. May 10, 2010

### Staff: Mentor

Re: Help with My complex functions :(

Your vector-valued function can be written this way:
f(t) = <(2 - i) e(-1 + 2i)t , (3 + 4i)e(-1 + 2i)t>

Then split up the exponentail parts using the fact that e(a + b)t = eatebt. Use the fact that eix = cosx + isinx. These should get you started.

6. May 10, 2010

### Char. Limit

Re: Help with My complex functions :(

Just moved the "e"s outside of the superscript for you.

7. May 10, 2010

### Staff: Mentor

Re: Help with My complex functions :(

Thanks. I hadn't noticed they were superscripts also.

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