7. [I1 Points] DETAILS MY NOTES PRACTICE ANOTHER Find all values ofx in the interval [0, 271] where f(x) = 7 sin(x) 7 cos(x) has a horizontal tangent line. (Enter your answers as a commaseparated list. Ifari answer does not exist, enter DNE.) X: Submit Answer 8. [I1 Points] DETAILS MY NOTES PRACTICE ANOTHER Given in) = 5, ml) = 4, me) = 3, g(0) = 1, g'(0) = s, and F(x) = f(g(x)), find F'(O). Submit Answer 9. [I1 Points] DETAILS MY NOTES PRACTICE ANOTHER Find the derivative of the function y defined implicitly in terms of X. x+y+4x2+3y3:4 EL: dx