- #1

DrClaude

Mentor

- 7,339

- 3,520

## Main Question or Discussion Point

I have a question on how to properly typeset a series of inequalities or approximate equalities when the LHS does not change. Take for example

[tex]

f(x) = \sin(x) \\

\quad \approx x - \frac{x^3}{3!} \\

\quad = x - \frac{x^3}{6}

[/tex]

What I did there is that I took it as if it was one long line,

[tex]

f(x) = \sin(x) \approx x - \frac{x^3}{3!} = x - \frac{x^3}{6}

[/tex]

that is split and stacked. Is this the correct way to do it? Or is it assumed that the LHS repeats, i.e.,

[tex]

f(x) = \sin(x) \\

f(x) \approx x - \frac{x^3}{3!} \\

f(x) = x - \frac{x^3}{6}

[/tex]

in which case the last line is incorrect?

[tex]

f(x) = \sin(x) \\

\quad \approx x - \frac{x^3}{3!} \\

\quad = x - \frac{x^3}{6}

[/tex]

What I did there is that I took it as if it was one long line,

[tex]

f(x) = \sin(x) \approx x - \frac{x^3}{3!} = x - \frac{x^3}{6}

[/tex]

that is split and stacked. Is this the correct way to do it? Or is it assumed that the LHS repeats, i.e.,

[tex]

f(x) = \sin(x) \\

f(x) \approx x - \frac{x^3}{3!} \\

f(x) = x - \frac{x^3}{6}

[/tex]

in which case the last line is incorrect?