show that the differential equation (on the left) is a solution of the function (on the right)
d^2u/dt^2 = a^2 * (d^2u/dx^2) u(x, t) = f(x-at) + g(x+at)

In the 30-60-90 triangle below side s has a length of and side r has a length

Mexico city, mexico, is the world's second largest metropolis and is also one of its fastest-growing cities with a projected growth rate of 3.2% per year. its population in 1991 was 20,899,000 people. use the formula p = 20.899e0.032t to predict its population p in millions with t equal to the number of years after 1991. what is the predicted population to the nearest thousand of mexico city for the year 2010?

The ratio of the measures of the three angles in a triangle is 2: 9: 4. find the measures of the angels