Need help. please. 8

Step-by-step explanation:

sin²(x) + cos²(x) = 1

cos²(x) = 1 - sin²(x)

cos(x/2) = ±sqrt((1 + cos(x))/2)

in our case

sin(x) = 1/4, tan(x) > 0, so cos(x) is positive too.

sin²(x) = 1/4² = 1/16

cos²(x) = 1 - 1/16 = 15/16

cos(x) = sqrt(15)/4

cos(x/2) = sqrt((1 + sqrt(15)/4)/2) = sqrt(1/2 + sqrt(15)/8) =

= sqrt(8/16 + 2×sqrt(15)/16) =

= 1/4 × sqrt(8 + 2×sqrt(15))

so, D is correct

15% chance.

step-by-step explanation:

3/10 times, the 5 year old will get a tablet. 5/10 times, the 13 yer old will get a tablet. multiply both fractions to get 15/100 times, both would have a tablet.