vortexring
New member
- Joined
- Oct 24, 2023
- Messages
- 2
In the above image, why (at the "6.25/j" section) in the next expression is the nominator and denominator multiplied by "-j". I can understand that you need a "j^2" in order to make it equivalent to "j^2=-1" but I don't understand the rule where you just multiply top and bottom by "-j" to get what you need, it doesn't seem to follow the usual algebraic rules, why aren't the other values in the expression also multiplied by "-j", why is it isolated to the fraction section of the expression?
Note: This is from an engineering maths book hence the use of "j" instead of "i"