For which value of a the system of ODES ₁ = sinh(y₁) + a tanh(y2), y2 = -2 cos(y₁) +2e³+32 + tanh(y₂), linearised around (y1, y2) = (0,0) displays an unstable focus? Select one: O a. a < -1/2 O b. a 2 = O c. -1/2 < a < 0 O d. 0 < a < 2

Evaluate (2 cs c x cot x + 4sec?x)dx. А. -2 csc x + 4 tan x + C В. 2 csc x + 4 tan x + C С. 2 csc x – 4 tan x + C D. -2 sec x +4 tan x + C

A B C please

What is the solution of the DE tan? x csc³ y dx = dy? cos³y A. tan x – x = cos y+ + c B. tan x = – cos y + cos³y + c cos3y + c C. x = - cos y + cos³y + c 3 D. tan x – x = - cos y + Answer: What is the order of y" + y" + y' + y = 0 A. Order 1 B. Order 2 C. Order 3 D. none Answer: