Ask Me Help Desk - Calc (Finding Exact Values)

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

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

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.