## anonymous one year ago If sinA = 2/3 find cos A/2 =? need help ASAP

1. misty1212

HI!!

2. misty1212

first find $$\cos(A)$$

3. misty1212

then use $\cos(\frac{A}{2})=\sqrt{\frac{1+\cos(A)}{2}}$

4. anonymous

HOW to get cos A?

5. misty1212

draw a triangle

6. misty1212

|dw:1438137818903:dw|

7. misty1212

there is a picture on an angle whose sine is $$\frac{2}{3}$$ find the third side via pythagoras

8. misty1212

once you have the missing side, you know the cosine let me know when you get it

9. anonymous

Oh i get it ... i'll give it a try... with some other exercises

10. anonymous