Consider the system of differential equations dxdt=−4ydydt=−4x. convert this system to a second order differential equation in y by differentiating the second equation with respect to t and substituting for x from the first equation. solve the equation you obtained for y as a function of t; hence find x as a function of t. if we also require x(0)=4 and y(0)=5, what are x and y?

What values of c and d make the equation true?

What is the point of inflection for the function f(x)=2cos4x on the interval (0, pi/2)

(50 ) mrs. julien’s and mrs. castillejo’s classes are selling cookie dough for a school fundraiser. customers can buy packages of macadamia nut chip cookie dough and packages of triple chocolate cookie dough. mrs. julien’s class sold 25 packages of macadamia nut chip cookie dough and 30 packages of triple chocolate cookie dough for a total of $221.25. mrs. castillejo’s class sold 5 packages of macadamia nut chip cookie dough and 45 packages of triple chocolate cookie dough for a total of $191.25. (a) write the system of equations that model the problem. be sure to explain which equation represents which situation. (b) find the cost of each type of cookie. show your work. (c) explain which method you used to solve the system and why you chose that method.