Another question i had was: If sin(alpha)=4/5 in quadrant 1 and
cos(beta)=-11/12 in quadrant II, find
Sin(alpha+beta)
Tan(alpha+beta)
Thats a LOT for the help.
Printable View
Another question i had was: If sin(alpha)=4/5 in quadrant 1 and
cos(beta)=-11/12 in quadrant II, find
Sin(alpha+beta)
Tan(alpha+beta)
Thats a LOT for the help.
You could get fancy and use the sum of angles formulas, but I think it's easier just to find alpha and beta:Quote:
Originally Posted by aussiekid90
$\displaystyle \alpha = sin^{-1} \left ( \frac{4}{5} \right ) \approx 0.927295 \, rad$
$\displaystyle \alpha$ is supposed to be 1st quadrant and, in fact, it is.
$\displaystyle \beta = cos^{-1} \left ( - \frac{11}{12} \right ) \approx 2.73045 \, rad$
which checks out as being in the 2nd quadrant.
So:
$\displaystyle sin(\alpha + \beta) = sin(3.65775)=-0.493542$
$\displaystyle tan(\alpha + \beta) = tan(3.65775) = 0.567471$
-Dan
