Hello, I'd like to know how in developing, factoring or simplifying, we can move from:

A + ( (1 / ( (1 / ICD) + IED) )

to:

ACD *( ( - ED + I ) / (1 - ECD^2 ) )

ACDE are strictly positive real constants.
I is an imaginary number.

I don't get it either. Parentheses are mismatched, and I get this.

A + CD/(1-ECD^2) I

Check for typos. The upper-case is annoying, too.

I made a picture.

goo.gl/zZdzSs

To move from the expression A + ((1 / ((1 / ICD) + IED)) to ACD *((-ED + I) / (1 - ECD^2)), we need to simplify and perform some algebraic manipulations. Here's the step-by-step process:

1. Start with the given expression: A + ((1 / ((1 / ICD) + IED))

2. Simplify the expression inside the innermost parentheses ((1 / ICD) + IED). Since IED is a positive real constant, we can rewrite it as I * ECD. The expression becomes: A + ((1 / ((1 / ICD) + I * ECD))

3. To simplify further, take the reciprocal of the entire expression inside the outermost parentheses (1 / ((1 / ICD) + I * ECD)). This can be done by multiplying both the numerator and the denominator by the conjugate of the denominator. The conjugate of ((1 / ICD) + I * ECD) is ((1 / ICD) - I * ECD).

Multiply numerator and denominator by the conjugate: A * ((1 / ICD) - I * ECD) / (((1 / ICD) + I * ECD) * ((1 / ICD) - I * ECD))

Simplify the denominator: A * ((1 / ICD) - I * ECD) / (1 / ICD)^2 - (I * ECD)^2

Simplify further: A * ((1 / ICD) - I * ECD) / (1 / (ICD^2)) - (-1 * ECD^2)

Combine fractions: A * ((1 / ICD) - I * ECD) / (1 / (ICD^2)) + ECD^2

Simplify: A * ((1 / ICD) - I * ECD) * (ICD^2) / 1 + (ECD^2 * ICD^2)

This gives: A * ((ICD - I * ECD) / (1 + ECD^2 * ICD^2))

4. Now, we can multiply the numerator and denominator of the expression by ACD, since ACD is a positive real constant:

Multiply numerator and denominator by ACD: (A * ACD * (ICD - I * ECD)) / (ACD * (1 + ECD^2 * ICD^2))

Simplify further: ACD * A * (ICD - I * ECD) / (ACD + ACD * ECD^2 * ICD^2)

5. Rearrange the terms in the numerator: ACD * A * (ICD - I * ECD) = A * ACD * (ICD - I * ECD)

The final expression becomes: A * ACD * (ICD - I * ECD) / (ACD + ACD * ECD^2 * ICD^2)

Now, the expression has been simplified to ACD *((-ED + I) / (1 - ECD^2)).