00:01
In this problem, we are provided with the differential equation y double prime plus 4 times y prime plus 4 times y equals to negative 6 times e raised to the power negative 2t.
00:15
And we need to solve this using variation of parameters method.
00:19
So first we consider the characteristic equation.
00:22
We have lambda squared plus 4 times lambda plus 4 equals to 0, which can be written as lambda plus 2 the whole squared.
00:31
Equals to 0 which implies that we have lambda to be equal to negative 2 and negative 2.
00:37
So this gives y 1 equals to e raised to the power negative 2 t and y2 equals to t times e raised to the power negative 2 t.
00:47
So now that we have found y 1 and y2 we can find out the wrong skin.
00:51
So we have the wrong skin to be given by the determinant of y 1, y2, y 1 prime, y2 prime.
00:59
So substituting the values we have the determi of e -rase to the power negative 2t, t times e r -rase to the power negative 2t.
01:08
The derivative of e -r -r -t -2 -t is negative 2 -t2 times e -r -r - to the par negative -t, and the derivative of t -t times e -r -r -megative 2t is e -rased to the par negative -2 -t.
01:24
This is obtained by the product rule of differentiation.
01:28
So now let us find the determinant.
01:31
We get e raised to the power negative 4 t times 1 minus 2 t plus 2 t times e raise to the power negative 40 so now let us simplify this we can factor out e raised to the power negative 40 so we get e raised to the power negative 40 times 1 minus 2 t plus 2 t so canceling out negative 2 t and positive 2 t we get e raised to the power and negative 40 so this is the value of the wrong skin.
02:02
Now that if we have found the wrong skin, we can find out u1 and u2.
02:06
We have u1 equals to integral y1g over wrong skin d t.
02:13
So substituting the values we have integral of e raised to the power negative 2t times negative 6 times e raised to the power negative 2t, the whole divided by e raised to the power negative 40 d t.
02:26
So clearly e r...