Determine whether the given function is a solution to the given differential equation.
1. x = 2 cos t - 3 sin t, x" + x = 0
2. y = sin x + x^2, d^2y/dx^2 + y = x^2 + 2
3. x = cos 2t, dx/dt + tx = sin 2t

In the figure below, ∠dec ≅ ∠dce, ∠b ≅ ∠f, and segment df is congruent to segment bd. point c is the point of intersection between segment ag and segment bd, while point e is the point of intersection between segment ag and segment df. the figure shows a polygon comprised of three triangles, abc, dec, and gfe. prove δabc ≅ δgfe.

G. how many different 6-letter arrangements can be formed using the letters in the word absent, if each letter is used only once? a. 6 b. 36 c. 720 d. 46,656

Use the irregular polygon below. show all work. a. find the perimeter. b. find the area. the angles of the irregular polygon is 2, 8, 8, and 4.