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[sascha]

How can I make the fx-CG500 simplify √-x into i√x?

The device is in complex mode.

It works if I replace x with either a real number or if with |x|, but the latter one doesn't work with a larger expression.

Edited by sascha, 02 July 2021 - 02:44 AM.

[SofiaJone]

Hi! This is not really a bug — it’s more about how the ClassPad handles symbolic expressions.

Mathematically, you are correct:

√(-x) = i√x (for x > 0)

However, the calculator does not always automatically rewrite expressions into this form when variables are involved. It usually keeps the original expression √(-x), even in complex mode, unless additional simplification rules are applied.

That’s why it works when you replace x with a number — because the calculator evaluates it numerically instead of symbolically.

A practical workaround is:

• Rewrite the expression manually as i√x
• Or evaluate it with a specific value of x

Also, if you just want to quickly check square root calculations (for real values or to verify steps), you can use an online tool like this:
https://lacalculador...c/<span></span>

It’s useful for basic operations and square root calculations when you want fast results.