In LaTeX, I want to create the following equation:

    $$x(t) = A1 sin(2 \pi f_1 t) + A2 sin(2 \pi f_2 t)$$


I don't want to show the multiplication sign. But is there a way to have a space where the multiplication sign would be? So for example between A1 and sin() ?

Also, how can I change the letter size of my equation?

Thanks for help!

• In math mode, you can use \, for thin space, \: for medium space, \; for thick space, \! for thin negative space. Also, ~ for full space. See LaTeX manual (Lamport, p. 52), for example. – Steven B. Segletes Jan 31 '17 at 12:35
• You should be using \sin. In the general case LaTeX will insert appropriate spacing for you, you shouldn't really need to do anything, but I suppose if you have a specific aesthetic, @StevenB.Segletes's suggestions above should do – Au101 Jan 31 '17 at 12:38
• If A1 doesn't denote A times 1 then normally it would be marked as A_1 for example, with a subscript. and use \sin then spacing should be correct without adding any extra spaces. – David Carlisle Jan 31 '17 at 12:48
• What is the concern about the font size of your math letters? – Jan Jan 31 '17 at 14:23

As Au101 pointed out, use \sin. Also, you presumably want a subscript on the A's.
\documentclass{article}
$$x(t) = A_1 \sin(2 \pi f_1 t) + A_2 \sin(2 \pi f_2 t)$$