What is infant mortality rate?

Step-by-step explanation:Infant mortality is the death of an infant before his or her first birthday. The infant mortality rate is the number of infant deaths for every 1,000 live births. ... In 2019, the infant mortality rate in the United States was 5.6 deaths per 1,000 live births. (See Mortality in the United States, 2019).,....

cosA = √(21/25)

Step-by-step explanation:

We know

sin²(A) + cos²(A) = 1

Next, we know that sin(A) = 2/5. Plugging that into our equation, we get

(2/5)² + cos²A = 1

4/25 + cos²A = 1

subtract 4/25 from both sides to isolate cos²A

cos²A = 1 - 4/25 = 25/25-4/25 = 21/25

square root both sides to get

cosA = √(21/25)

We do not include -√(21/25) in our possible answer for cosA because this is in quadrant 1, so cosA must be positive.