Which of the following functions are solutions of the differential equation y'' + y = 9 sin(x)?
1.) y = 9x/2 sin(x)
2.) y=9 cos(x)
3.) -9x/2 cos(x)
4.) 9 sin(x)
5.) 9x sin(x) - 6x cos(x)

Ur environment is very sensitive to the amount of ozone in the upper atmosphere. the level of ozone normally found is 4.04.0 parts/million (ppm). a researcher believes that the current ozone level is not at a normal level. the mean of 2525 samples is 4.44.4 ppm with a standard deviation of 0.80.8. assume the population is normally distributed. a level of significance of 0.020.02 will be used. make the decision to reject or fail to reject the null hypothesis. answer tables