Find the exact value of the following under the given conditions:

(Please follow the link for the equation, thanks!)

http://i96.photobucket.com/albums/l194/anti-you92/Capture33.png

There seems to be an error in the equation, which is written as:


\tan \alpha = -4/3,\ \pi/2, \ < \alpha < - cos \beta = 1/2, \ 0< \beta < \pi/2


Note that \alpha is an angle, whereas cos \beta is not - so it looks like something is missing in the inequality. Also, the commas are misplaced. Consequently it's impossible to determine a value for \cos \beta .

But as for determining sin \alpha and \cos \alpha from \tan\alpha = -4/3 - you can do that by drawng out a 3-4-5 right triangle and applying the definitions of sin and cosine.