Package inputenc Error: Unicode char ̂ (U+302)(inputenc) not set up for use with LaTeX. … $\widehat{\left (OA,AA' \right )}$

Question

I'm writing my dissertation in Portuguese but the latex is finding this kind of error. In fact, I'm using some mathematical characters. How do I resolve this? Here below is the location of the error in the latex source code. Thank you

Sendo que as tensões de entrada $U_{OA}$ e a de saída $U_{OA'}$ são constantes e iguais e o ângulo projetado entre essas tensões é igual a $7,5^{\circ}$, então deduz que os ângulos $\widehat{\left (OA,AA' \right )}$ e ̂$\widehat{\left ( AA,A'O \right )}$ são iguais a  $86,25^{\circ}$, mostrado na figura \ref{diagramafasauto}. Note-se que Co representa a extensão de C (fase c) e OCo a bissetriz do ângulo $\widehat{\left ( OA,AB \right )}$, então o valor do ângulo  $\widehat{\left ( OA,OCo \right )}$ é igual a $60^{\circ}$. Deduz-se então o ângulo  $\widehat{\left ( OA',OCo \right )}$.

Answer 1

In the following part of your input,

então deduz que os ângulos $\widehat{\left (OA,AA' \right )}$ e ̂$\widehat{\left ( AA,A'O \right )}$ são iguais

specifically this part:

)}$ e ̂$\widehat

the sequence of Unicode characters between the dollar signs (inclusive) is:

‎U+0024  DOLLAR SIGN
‎U+0020  SPACE
‎U+0065  LATIN SMALL LETTER E
‎U+0020  SPACE
‎U+0302  COMBINING CIRCUMFLEX ACCENT
‎U+0024  DOLLAR SIGN

You may not be able to see it in your editor or here, but if you copy and paste it into a Unicode character viewer like this one, you will be able to see it.

That U+0302 COMBINING CIRCUMFLEX ACCENT is meaningless there, and you probably don't want it. What you want there between (strictly) the dollar signs is probably just e. With just this change to your input, it works:

\documentclass{article}
\usepackage[utf8]{inputenc}
\begin{document}

Sendo que as tensões de entrada $U_{OA}$ e a de saída $U_{OA'}$ são constantes e iguais e o ângulo projetado entre essas tensões é igual a $7,5^{\circ}$, então deduz que os ângulos $\widehat{\left (OA,AA' \right )}$ e $\widehat{\left ( AA,A'O \right )}$ são iguais a  $86,25^{\circ}$, mostrado na figura \ref{diagramafasauto}. Note-se que Co representa a extensão de C (fase c) e OCo a bissetriz do ângulo $\widehat{\left ( OA,AB \right )}$, então o valor do ângulo  $\widehat{\left ( OA,OCo \right )}$ é igual a $60^{\circ}$. Deduz-se então o ângulo  $\widehat{\left ( OA',OCo \right )}$.

\end{document}

producing:

---

That solves the problem, but note that without the fix, TeX actually tells you everything you need to know, pointing out the exact character at which there is a problem:

l.5 ...los $\widehat{\left (OA,AA' \right )}$ e ̂
                                                  $\widehat{\left ( AA,A'O \...

— the top line is everything that was read before the error happened, and the bottom line is what is not yet read.

A word of advice: you can avoid such super-long lines in your input. TeX (by default) treats a single newline character as equivalent to a space, so you may have an easier time debugging errors (if you don't take time to learn the error-line format) if you have shorter lines. (Of course, long lines are not a problem if you know how to deal with them.)