Answer18:
The quadrilateral ABCD is not a parallelogram
Answer19:
The quadrilateral ABCD is a parallelogram
Step-by-step explanation:
For question 18:
Given that vertices of a quadrilateral are A(-4,-1), B(-4,6), C(2,6) and D(2,-4)
The slope of a line is given m=
Now,
The slope of a line AB:
m=
m=
m=
The slope is 90 degree
The slope of a line BC:
m=
m=
m=
The slope is zero degree
The slope of a line CD:
m=
m=
m=
The slope is 90 degree
The slope of a line DA:
m=
m=
m=
m=
The slope of the only line AB and CD are the same.
Thus, The quadrilateral ABCD is not a parallelogram
For question 19:
Given that vertices of a quadrilateral are A(-2,3), B(3,2), C(2,-1) and D(-3,0)
The slope of a line is given m=
Now,
The slope of a line AB:
m=
m=
m=
The slope of a line BC:
m=
m=
m=
m=3
The slope of a line CD:
m=
m=
m=
The slope of a line DA:
m=
m=
m=3
The slope of the line AB and CD are the same
The slope of the line BC and DA are the same
Thus, The quadrilateral ABCD is a parallelogram
Answer:
So, solution of the differential equation is

Step-by-step explanation:
We have the given differential equation: y′′+4y=5xcos(2x)
We use the Method of Undetermined Coefficients.
We first solve the homogeneous differential equation y′′+4y=0.

It is a homogeneous solution:

Now, we finding a particular solution.

we get

So, solution of the differential equation is

1. Subtract 4 from both sides
v - 4 = 2t
2. Divide both sides by 2
v - 4/2 = t
3. Switch sides
t = v - 4/2
18 - (8 - 3 • (2t + 5)) = 0
6t + 25 = 0
3.1 Solve : 6t+25 = 0
Subtract 25 from both sides of the equation :
6t = -25
Divide both sides of the equation by 6:
t = -25/6 = -4.167
Final answer is
t = -25/6 = -4.167