# complex equation

• Jan 28th 2010, 07:03 AM
avazim
complex equation
I wonder if some one can help me with:

1. to solve the equation

2. to make the function with the e below to loran column

I know it seems simple but for me it is a big help
thank's alot
• Jan 29th 2010, 03:38 AM
HallsofIvy
Quote:

Originally Posted by avazim
I wonder if some one can help me with:

1. to solve the equation

2. to make the function with the e below to loran column

I know it seems simple but for me it is a big help
thank's alot

Solving the equation is pretty trivial isn't it? If $cos^2(z)= -2$ then either $cos(z)= i\sqrt{2}$ or $cos(z)= -i\sqrt{2}$. If your calculator does not allow for inverse trig functions of imaginary numbers (my TI 89 does), use $cos(z)= \frac{e^z+ e^{-z}}{2}= \pm i\sqrt{2}$. Letting $u= e^z$ makes the equation $u^2+ 1= \pm 2 i\sqrt{2} u$ that you can solve with the quadratic equation.

For (2), I simply don't know what you mean by " function with the e below to loran column".