Given #sin theta=4/5#, #theta# lies in Quadrant 2, find #cos theta/2# ?
1 Answer
Mar 14, 2018
Explanation:
It lies in the second quadrant
So here is what I know:
Sin(y-value) is positive
Cos(x-value) is negative
I also know that
Therefore:
We can either use Pythagorean theorem to find the length of the adjacent leg or we can apply a Pythagorean triple:
Pythagorean Theorem:
Manipulated to:
Since 4 is supposed to be the Cos value, we will use
Therefore: