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.

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- May 8th 2006, 01:09 PMaussiekid90Ugh, More Trig Stuff
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. - May 8th 2006, 01:52 PMtopsquarkQuote:

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