Answer:
1.10
Step-by-step explanation:
Recall that variation of parameters is used to solve second-order ODEs of the form
<em>y''(t)</em> + <em>p(t)</em> <em>y'(t)</em> + <em>q(t)</em> <em>y(t)</em> = <em>f(t)</em>
so the first thing you need to do is divide both sides of your equation by <em>t</em> :
<em>y''</em> + (2<em>t</em> - 1)/<em>t</em> <em>y'</em> - 2/<em>t</em> <em>y</em> = 7<em>t</em>
<em />
You're looking for a solution of the form
![y=y_1u_1+y_2u_2](https://tex.z-dn.net/?f=y%3Dy_1u_1%2By_2u_2)
where
![u_1(t)=\displaystyle-\int\frac{y_2(t)f(t)}{W(y_1,y_2)}\,\mathrm dt](https://tex.z-dn.net/?f=u_1%28t%29%3D%5Cdisplaystyle-%5Cint%5Cfrac%7By_2%28t%29f%28t%29%7D%7BW%28y_1%2Cy_2%29%7D%5C%2C%5Cmathrm%20dt)
![u_2(t)=\displaystyle\int\frac{y_1(t)f(t)}{W(y_1,y_2)}\,\mathrm dt](https://tex.z-dn.net/?f=u_2%28t%29%3D%5Cdisplaystyle%5Cint%5Cfrac%7By_1%28t%29f%28t%29%7D%7BW%28y_1%2Cy_2%29%7D%5C%2C%5Cmathrm%20dt)
and <em>W</em> denotes the Wronskian determinant.
Compute the Wronskian:
![W(y_1,y_2) = W\left(2t-1,e^{-2t}\right) = \begin{vmatrix}2t-1&e^{-2t}\\2&-2e^{-2t}\end{vmatrix} = -4te^{-2t}](https://tex.z-dn.net/?f=W%28y_1%2Cy_2%29%20%3D%20W%5Cleft%282t-1%2Ce%5E%7B-2t%7D%5Cright%29%20%3D%20%5Cbegin%7Bvmatrix%7D2t-1%26e%5E%7B-2t%7D%5C%5C2%26-2e%5E%7B-2t%7D%5Cend%7Bvmatrix%7D%20%3D%20-4te%5E%7B-2t%7D)
Then
![u_1=\displaystyle-\int\frac{7te^{-2t}}{-4te^{-2t}}\,\mathrm dt=\frac74\int\mathrm dt = \frac74t](https://tex.z-dn.net/?f=u_1%3D%5Cdisplaystyle-%5Cint%5Cfrac%7B7te%5E%7B-2t%7D%7D%7B-4te%5E%7B-2t%7D%7D%5C%2C%5Cmathrm%20dt%3D%5Cfrac74%5Cint%5Cmathrm%20dt%20%3D%20%5Cfrac74t)
![u_2=\displaystyle\int\frac{7t(2t-1)}{-4te^{-2t}}\,\mathrm dt=-\frac74\int(2t-1)e^{2t}\,\mathrm dt=-\frac74(t-1)e^{2t}](https://tex.z-dn.net/?f=u_2%3D%5Cdisplaystyle%5Cint%5Cfrac%7B7t%282t-1%29%7D%7B-4te%5E%7B-2t%7D%7D%5C%2C%5Cmathrm%20dt%3D-%5Cfrac74%5Cint%282t-1%29e%5E%7B2t%7D%5C%2C%5Cmathrm%20dt%3D-%5Cfrac74%28t-1%29e%5E%7B2t%7D)
The general solution to the ODE is
![y = C_1(2t-1) + C_2e^{-2t} + \dfrac74t(2t-1) - \dfrac74(t-1)e^{2t}e^{-2t}](https://tex.z-dn.net/?f=y%20%3D%20C_1%282t-1%29%20%2B%20C_2e%5E%7B-2t%7D%20%2B%20%5Cdfrac74t%282t-1%29%20-%20%5Cdfrac74%28t-1%29e%5E%7B2t%7De%5E%7B-2t%7D)
which simplifies somewhat to
![\boxed{y = C_1(2t-1) + C_2e^{-2t} + \dfrac74(2t^2-2t+1)}](https://tex.z-dn.net/?f=%5Cboxed%7By%20%3D%20C_1%282t-1%29%20%2B%20C_2e%5E%7B-2t%7D%20%2B%20%5Cdfrac74%282t%5E2-2t%2B1%29%7D)
If I'm understanding this correctly you mean:
If a vertical line does not connect to more than one point in a relation then that relation is a function.
Then your answer is A-True.
That is called the vertical line test. The vertical line cannot touch more than one point at the same time if it is a function. If it does touch then it is not a function.
Answer: 43.25?
Step-by-step explanation: