Question

Consider the differential equation y '' − 2y ' + 5y = 0; ex cos(2x), ex sin(2x), (−[infinity], [infinity]). Verify that the given functions form a fundamental set of solutions of the differential equation on the indicated interval. The functions satisfy the differential equation and are linearly independent since W(ex cos(2x), ex sin(2x)

Answer 1

Answer:

Step-by-step explanation:

Characteristic equation:

$\lambda^2-2\lambda + 5 =0$

$\lambda = 1\pm2i$

The solution of the ODE is

$y = e^x(C_1 cos(2x) + C_2 sin(2x) )$

Now, very find by taking the first and the second derivative of y.

$y' = e^x(-2 C_1 sin (2x) +2C_2 cos (2x)) +e^x (C_1 cos (2x) + C_2sin(2x))$

$=-2e^xC_1 sin(2x) +2e^xC_2 cos (2x)+C_1e^xcos(2x) + C_2e^x sin(2x)$

$y" = -2e^x C_1 sin(2x) -4e^x C_1cos(2x)+2e^xC_2cos(2x)-4e^xC_2sin(2x) +C_1e^x cos(2x) -2C_1e^xsin(2x)+C_2e^x sin(2x) +2C_2e^x cos(2x)$

$=-4C_1e^xsin(2x) -3C_1e^x cos(2x) +4C_2e^xcos(2x) -3C_2e^xsin(2x)$

Now, put all in y" -2y'+5y and consider if it = 0 or not.