For the differential equation y(n)+p1(t)y(n−1)+ ... +pn(t)y=0 with solutions y1, ..., yn Abel's formula for the Wronskian is W(y1,...,yn)(t)=Ce−∫p1(t)dt. Use Abel's formula to find the Wronskian of a fundamental set of solutions of the differential equation y′′′+7y′′−y′−3y=0.

If sin(x) = 0 and cos(x) = 1, what is tan(x)?

Two sides of a right triangle measure 2 units and 4 units. what is the area of the square that shares a side with the third side of the triangle?

Researchers are conducting experiments to determine the role of alcohol in the development of depression. after the study is complete, they determine that the relative risk of developing depression is 1.55 with a 95 % ci of 1.2 -1.9. each group is then divided into nonsmokers and smokers. the relative risk for the nonsmokers is 1.12 with a 95% ci of 0.87-1.37. the relative risk for the smokers is 1.7 with a 95 % cl of 1.5-1.9. what type of bias may affect this study? a. procedure bias b. recall bias c. selection bias d. confounding e. lead-time bias