## anonymous 5 years ago i need to find the tan(a-b) knowing tan a=5/12, sin $= -4/5 and sec B= 25/24 the restriction is (pi/2)<$<a<(3pi/2)<B<2pi. This is for precalc class and is kind of my last resort... I don't know how this site works actually, but please help ^^

1. anonymous

\$ is theta by the way.... ._.

2. anonymous

$tan^{-1}(a-b)=\frac{tan(a)-tan(b)}{1+tan(a)tan(b)}$ so you need to find $tan(a)$ and $tan(b)$ you already have $tan(a)=\frac{5}{12}$ $sin(b)=-\frac{4}{5}$ $cos(b)=\frac{24}{25}$ because secant is the reciprocal of cosine, so $tan(b)=-\frac{5}{6}$ because it is sine over cosine. plug these numbers into the formula and you win.

3. anonymous

NO YOU WIN! XD