Title: sqrt(custom_symbol) does not render properly as \sqrt{} but as \mathrm{sqrt}

[SpazzNon]

Hi Connor,

First of all, thank you for creating handcalcs — since I discovered it, I haven't stopped using it! I'm from Peru, and I'm planning to run a small workshop to introduce this amazing tool to people who are just starting with Python.

I'm currently facing an issue when using custom_symbols with the square root function.

Here's my setup:

handcalcs.set_option("custom_symbols", {
    "fcmag": "\\left( f'_{c} \\right)",
    "fymag": "f_y",
    "rhobal": "\\overline{ \\rho_b }",
    "fraccion": r"\frac{k_x \text{Holaj}x}{r_x} "
})

I use Pint for units:

f_prime_c = 210 * kgf/cm**2
fcmag = f_prime_c.magnitude  # This is a float

The issue occurs with the square root:

%%render
As_min_1 = max(0.80*sqrt(fcmag)/fymag*b*d_1, 14/fymag*b*d_1)

Expected LaTeX Output:

\sqrt{f'_{c}}

Actual Output (from %%tex):

\mathrm{sqrt} f'_{c}

This incorrect rendering only happens when using fcmag (a custom_symbol). If I use f_prime_c directly in the formula, it renders correctly as \sqrt{210}.

It seems the symbolic substitution breaks proper detection of sqrt() and falls back to rendering it as \mathrm{sqrt} instead of \sqrt{}.

Would love to hear your thoughts or guidance on how to patch this. I’ve been customizing the library, so I’d also be happy to contribute a fix or test one if you have suggestions.

Thanks again for your work!

Best regards

[av-engineering]

I would avoid using sqrt. Use **.5 instead: