Sono le formule più importanti. Con esse si ottengono tutte le altre formule, attraverso la loro manipolazione.

$$ sen(\color{#008080}{\alpha} + \color{#d4196a}{\beta}) = cos(\color{#008080}{\alpha})sen(\color{#d4196a}{\beta}) - sen(\color{#008080}{\alpha})cos(\color{#d4196a}{\beta}) $$ $$ sen(\color{#008080}{\alpha} - \color{#d4196a}{\beta}) = cos(\color{#008080}{\alpha})sen(\color{#d4196a}{\beta}) + sen(\color{#008080}{\alpha})cos(\color{#d4196a}{\beta}) $$ $$ cos(\color{#008080}{\alpha} + \color{#d4196a}{\beta}) = cos(\color{#008080}{\alpha})cos(\color{#d4196a}{\beta}) + sen(\color{#008080}{\alpha})sen(\color{#d4196a}{\beta}) $$ $$ cos(\color{#008080}{\alpha} - \color{#d4196a}{\beta}) = cos(\color{#008080}{\alpha})cos(\color{#d4196a}{\beta}) - sen(\color{#008080}{\alpha})sen(\color{#d4196a}{\beta}) $$
$$ \diamond $$