Cuál es la amplitud de la función trigonométrica de f(x)= -sen(x)

In a class, there are 12 girls. if the ratio of boys to girls is 5: 4 how many boys are there in the class

Me. i can't figure out this question. give an explanation too. .

Onnie is considering doing some long term investing with money that she inherited. she would like to have $50,000 at the end of 30 years. approximately how much money would lonnie need to put into an account earning 6% interest compounded annually in order to meet her goal?