I'm having issues understanding as to how to go about doing this. I cant seem to figure out how to find the values of sin and tan in terms of the given cos value in the 3rd quadrant. Thanks with any and all help.
$\cos[\theta] = \frac{-4}{5}$ and theta is in the 3rd quadrant, find the exact values of
(i) $\sin[\theta]$
(ii) $\tan[\theta]$
Best Answer
This is a table that expresses sin, cos and tan in terms of each other.
You don't need to remember the table... just substitute values in the triangle, find the third side using Pythagoras and find the value of the required function.
Also, you just need to remember which trigonometric function is positive in which quadrant using this table.
This can be remembered using the simple mnemonic.. After School To College.