First graded homework (due 9/8)
For maximal credit, full working must be shown.

(3 points.)
At time t (in years), the price of a gallon of gas is $y(t) . If
10y' = y ,
how long does it take for the price to double? Give your answer rounded to the nearest whole number of years.

(4 points.)
Solve the initial value problem
y' + y = e^{t}
with y(0) = 1 .

(3 points.)
Give an implicit solution to the initial value problem
y'(x) = ( 1 + 4x^{3}) / ( 1 + 4y)
with y(1) = 3 .
