Find values of m so that the function y = emx is a solution of the given differential equation.
(i) y + 2y = 0 (ii) y” – 5y’ + 6y = 0
A differential equation is an equation that involves the derivative (derivatives) of the dependent variable with respect to the independent variable (variables) is called a differential equation.
Answer: The values of m so that the function y = emx is a solution of the given differential equation is: (i) m = -2, (ii) m = 3, 2
Let's look into the steps below
Explanation:
Given: y = emx -------------- (1)
(i) y + 2y = 0
Let's differentiate (1) with respect to x
⇒ dy/dx = y' = memx --------------- (2)
⇒ y' = m × y, using (1)
⇒ y' - my = 0
Comparing y' - my = 0 with the given equation y + 2y = 0,
We observe that,
m = -2
(ii) y” – 5y’ + 6y = 0
Let's differentiate (2) with respect to x again
⇒ d2y / dx2 = y'' = m2emx --------------- (3)
Substituting (1), (2) and (3) in the given equation y” – 5y’ + 6y = 0 we get,
⇒ m2emx - 5memx + 6emx = 0
Dividing the above equation throughout by emx we get,
⇒ m2 - 5m + 6 = 0
By splitting the middle term we get,
⇒ m2 - 3m - 2m + 6 = 0
⇒ m(m - 3) - 2(m - 3) = 0
⇒ (m - 3) (m - 2) = 0
Thus, m = 3, 2
Hence, the values of m so that the function y = emx is a solution of the given differential equation is: (i) m = -2, (ii) m = 3, 2
visual curriculum