Hey there! I'm happy to help!
Let's think of this angle being put inside of a unit circle (a circle with a radius of one). This angle is going to stay inside the first quadrant, so all of its trigonometric ratios will be positive.
We are given that the sin of x is 1/5. To get the x by itself, we can just find the inverse sine of both sides to isolate the x.
x=sin
(1/5)
x≈ 11.536959
2x≈ 23.073918
Now, we just cosine this value.
cos2x≈ 0.92
I hope that this helps! Have a wonderful day!