Phương trình vi phân y'' - 2y' -3y =0 có nghiệm tổng quát là ?
Answer:
y = c1 e^-x + c2 e^(3x)
Step-by-step explanation:
Review linear DE's
(D-3)(D+1)y = 0
Write this as an algebraic expression:
You have $100 and make $25 a day
Answer:
25d + 100
Step-by-step explanation:
I will call "d" the days passed
25d + 100
A. 0
B. Nonexistent
C. 1
D. -1
Answer:
[tex]\displaystyle \lim_{x\rightarrow 0^{+}} \frac{x\ln x}{\tan x}=-\infty\implies \text{B. Nonexistent (best answer)}[/tex]
Step-by-step explanation:
Recall L'Hopital's rule:
[tex]\displaystyle \lim_{x\rightarrow c}\frac{f(x)}{g(x)}=\lim_{x\rightarrow c}\frac{f'(x)}{g'(x)}[/tex]
First derivative of [tex]x\ln x[/tex]:
Recall the product rule:
[tex](f\cdot g)'=f'\cdot g+g'\cdot f[/tex]
[tex]\displaystyle \frac{d}{dx} (x\ln x)=\frac{d}{dx}(x)\cdot \ln (x)+\frac{d}{dx}(\ln x)\cdot x[/tex]
Note that:
[tex]\displaystyle \frac{d}{dx}(x)=1,\\\frac{d}{dx}(\ln (x))=\frac{1}{x}[/tex]
Simplifying, we get:
[tex]\displaystyle \frac{d}{dx} (x\ln x)=1\cdot \ln x+\frac{1}{x}\cdot x,\\\frac{d}{dx}(x\ln x)=\ln x+1[/tex]
First derivative of [tex]\tan x[/tex]:
[tex]\displaystyle \frac{d}{dx}(\tan x)=\sec^2 x[/tex]
Therefore, we have:
[tex]\displaystyle \lim_{x\rightarrow 0^{+}}\frac{x\ln x}{\tan x}=\lim_{x\rightarrow 0^{+}}\frac{\ln x+1}{\sec^2{x}}[/tex]
By definition, [tex]\cos x=\frac{1}{\sec x}[/tex]. Therefore,
[tex]\displaystyle \lim_{x\rightarrow 0^{+}}\frac{x\ln x}{\tan x}=\lim_{x\rightarrow 0^{+}}\frac{\ln x+1}{\sec^2{x}}=\lim_{x\rightarrow 0^{+}}\cos^2x(\ln x+1)[/tex]
Note:
[tex]\displaystyle \lim_{x\rightarrow 0^{+}}\cos^2x=1,\\\lim_{x\rightarrow 0^{+}}\ln x+1=-\infty[/tex]
Substitute:
[tex]\displaystyle \lim_{x \rightarrow0^{+}} \cos^2x(\ln x+1)=1\cdot (-\infty)=-\infty[/tex]
Therefore, we have:
[tex]\displaystyle \lim _{x\rightarrow 0^{+}}\frac{x\ln x}{\tan x}=-\infty \text{}[/tex], which best corresponds with [tex]\boxed{\text{B. Nonexistent}}[/tex]
*Commentary:
Technically speaking, a limit exists only if it is equal to a real number. By proper definition, infinity is not a number. With that being said, you will see limits expressed as infinity or negative infinity.
Here's what I will say about this specific problem.
The problem is stipulating that we approach [tex]x[/tex] from the right side. Because of this condition, it may be unorthodox to say this limit doesn't exist. However, if the problem just asked for [tex]\displaystyle \lim_{x\rightarrow 0}\frac{x\ln x}{\tan x}[/tex], it is common and preferred to say this limit does not exist, since [tex]\displaystyle \lim_{x\rightarrow 0^{-}}\frac{x\ln x}{\tan x}\neq \displaystyle \lim_{x\rightarrow 0^{+}}\frac{x\ln x}{\tan x}[/tex].
For example, [tex]\displaystyle \lim_{x\rightarrow 0}\frac{1}{x}=\text{DNE}[/tex], because [tex]\displaystyle \lim_{x\rightarrow 0}\frac{1}{x}[/tex] diverges. In other words, [tex]\displaystyle \lim_{x\rightarrow 0^{-}}\frac{1}{x}=-\infty \neq \displaystyle \lim_{x\rightarrow 0^{+}}\frac{1}{x}=\infty[/tex].
But again, the problem is asking for the limit as [tex]x[/tex] approaches from the right, in which case [tex]\displaystyle \lim _{x\rightarrow 0^{+}}\frac{x\ln x}{\tan x}=-\infty }[/tex]. It's really a pedagogical choice whether to say a limit equal to infinity or negative infinity exists or not since infinity implies there is no limit, so saying the limit of something is infinity becomes an oxymoron. In this case, the person who wrote the answer choices chose to express a limit of infinity as nonexistent, but it is worth mentioning that someone else solving this problem might express [tex]-\infty[/tex] as the answer, and they would be just as, if not more, correct.
Without resorting to L'Hopital's rule, recall that
[tex]\displaystyle \lim_{x\to0}\frac{\sin(ax)}{ax} = 1[/tex]
for a ≠ 0. Then
[tex]\displaystyle \lim_{x\to0^+} \frac{x \ln(x)}{\tan(x)} = \lim_{x\to0^+}\frac x{\sin(x)} \times \lim_{x\to0^+}\cos(x) \times \lim_{x\to0^+}\ln(x)[/tex]
The first two limits exist and are equal to 1, but the last limit is -∞.
How do you calculate frequency? If there are 138 bright white phones out of 1301 total phones, how do I calculate the frequency?
300000000000000000000000
Please I need help the picture below with the options
9514 1404 393
Answer:
(B) Function 2
Step-by-step explanation:
We can compute the slope of Function 2 using the slope formula.
m = (y2 -y1)/(x2 -x1) . . . . where x and y are the independent and dependent variables.
m = (0.2 -0.8)/(3 -2) = -0.6
The slope of Function 1 is about ...
-3/7 ≈ -0.43
The slope of Function 2 is more negative.
__
On a graph, the line representing function 2 has a steeper downward slope.
A rectangles length is 6 units greater than its width. Write an equation expressing the rectangles area, A, as a function of W
Answer:
A = W² + 6W
Step-by-step explanation:
The width is W.
The length is 6 units greater than the width, so the length is W + 6.
The area is the product of the length and width.
A = (W + 6)W
A = W² + 6W
If no sides of a triangle have the same length, the triangle is called scalene
(pronounced SKAY-leen). And, as you might remember, if the triangle has at
least two sides that are the same length, the triangle is called isosceles. Use the
markings or description in each diagram below to decide if AABC is isosceles or
scalene. Assume the diagrams are not drawn to scale.
Answer:
a. isosceles
b. isosceles
c. scalene
Formula to find perimeter of rectangle
Hey there!
The formula to find the perimeter of a rectangle is "P=2(l+w)".
Hope this helps!
Have a great day! :)
Answer:
formula to find the perimeter of rectangle is
2(l+b)hope it helps
stay safe healthy and happy.
Can someone help me with this please?
Solve for K
20-6 + 4K =2-2k
Answer:
K = -2Step-by-step explanation:
20-6 + 4K =2-2k
=> 14 + 4k = 2 - 2k
=> 4k + 2k = 2 - 14
=> 6k = -12
[tex] = > k = \frac{ - 12}{6} [/tex]
=> K = -2 (Ans)
Is 1 3/4 closer to 1 or 2 ? Explain your answer
Answer:
it's closer to 2
Step-by-step explanation:
In order to get to 1 from that number, you have to subtract 3/4. In order to get to 2 from that number, you only have to add 1/4. Clearly, the jump in adding is smaller than the jump to subtracting, which means it's closer to 2.
The number is closer to 2
What is fraction?A fraction shows part of a whole. This whole can be a region or a collection. The word fraction is derived from the Latin word "fractio" which means 'to break'. The Egyptians, being the earliest civilization to study fractions, used fractions to resolve their mathematical problems, which included the division of food, supplies, and the absence of a bullion currency.
All fractions consist of a numerator and a denominator and they are separated by a horizontal bar known as the fractional bar.
The denominator indicates the number of parts in which the whole has been divided into. It is placed in the lower part of the fraction below the fractional bar.The numerator indicates how many sections of the fraction are represented or selected. It is placed in the upper part of the fraction above the fractional bar.Given number:
1 3/4 = 7/4
On dividing
7/4 = 1.75
Hence, the number is closer to 2.
Learn more about fraction here:
https://brainly.com/question/10354322
#SPJ2
PLEASE HELP
write and solve an equation to find the value of X. please explain in details and show your work!
Answer:45 degrees
Step-by-step explanation:
a right triangle has a hypotenuse of length 2 inches. if one angle is 38°, find the length of each leg
Answer:
21
Step-by-step explanation:
what number is represented by 6 hundreds 14 tens and 12 ones?
Answer:
6 * 100 = 600
14 * 10 = 140
12 * 1 = 12
------------------------
752
Arrange the decimal numbers from largest to smallest.
Answer:
0.845, 0.839, 0.748, 0.712, 0.643
Answer:
0.845, 0.839,0.748,0.712,0.643
2. STEM A circuit board manufacturer rejects a 100-ohm resistor if its measured resistance is 0.15 ohm more than or less than 100 ohms. Resistors A and B are rejected. Resistor A's resistance differs from 100 ohms by 0.15 ohm. Resistor B's resistance differs from 100 ohms by -0.78 ohm. How do the resistances of these two resistors compare? Explain.
The comparison of both resistors is defined by an inequality. Resistor A has a higher resistance than resistor B because [tex]100.15\Omega > 99.22\Omega[/tex]
Given that:
[tex]R = 100 \Omega[/tex] ---- the reference resistor
First, we calculate the resistance of both resistors
Resistor A differs by [tex]0.15\Omega[/tex] means that:
[tex]R_A = 100\Omega + 0.15\Omega[/tex]
[tex]R_A = 100.15\Omega[/tex]
Resistor A has a resistance of [tex]100.15\Omega[/tex]
Resistor B differs by [tex]-0.78\Omega[/tex] means that:
[tex]R_B = 100\Omega -0.78\Omega[/tex]
[tex]R_B = 99.22\Omega[/tex]
Resistor B has a resistance of [tex]99.22\Omega[/tex]
By comparing the calculated values, we can conclude that:
Resistor A has a higher resistance than resistor B because [tex]100.15\Omega > 99.22\Omega[/tex]
Read more about inequality comparison at:
https://brainly.com/question/11772136
The product of 4x and 0 is:
a- 4x
b- 4
c- 0
d- none of these
A student rotated figure A 270° clockwise about the origin to create figure D. Evaluate whether the student performed the rotation correctly.
Step-by-step explanation:
The student incorrectly performed a rotation of 90° clockwise.
Answer:
C, the student incorrectly preformed a rotation of 90 degrees clockwise.
Step-by-step explanation:
5x+8=3(x+2) anyone know the answer?
Step-by-step explanation
work out the question in bracket first then separate numericals and variables to make it easier.
Answer:
distribute
5 + 8 = 3 ( + 2 )
expand to
5 + 8 = 3 + 6
subtract 8 from both sides
5 + 8 = 3 + 6
5 + 8 − 8 = 3 + 6 − 8
simplify
5 = 3 − 2
subtract 3 from both sides
5 − 3 = 3 − 2 − 3
simplify
2 = − 2
then divide both sides by 2
2 / 2 = − 2/ 2
= − 2/ 2
answer is
= −1
Step-by-step explanation:
Hope that helps>3
Help!!!!!!!!!!!!!!
2x+3=x-7
Answer:
x = - 10Step-by-step explanation:
2x+3=x-7
=> 2x - x = - 7 - 3
=> x = -10 (Ans)
Find the slope and the y-intercept of the line.
Answer:
slope=-1/5
y intercept=8
Hope this helps
Step-by-step explanation:
Answer:
Slope = -1/5
y-intercept: 8
Step-by-step explanation:
The line equation is y = mx + b, where m is the slope and b is the y-intercept.
We see that m is replaced by -1/5 and that b is replaced by 8.
Hope this helps!
Simplify (3x-1)(x+3)
Answer:
3x 2 +8x−3
Step-by-step explanation:
Answer:
3x^2+8x-3
Step-by-step explanation:
That should be the right answer but don't quote me on it.
the sum of 3 and a number
Answer:
the number will vary the answer
Step-by-step explanation:
3×1=3
3×2=6
What’s the answer ASAP
Answer:
none
Step-by-step explanation:
38×2=76
43×2=86
45×2=90
A store advertises a sale on t-shirts. The advertised price is four t-shirts for $48. Write and solve an equation to find the cost of one t-shirt.
a.) $8
b.) $12
c.) $16
d.) $48
S...
Find the length of UT.
12
T
14
W
2x+2
2x + 5
V
A. 32
B. 43
O o
C. 21
D. 39
9514 1404 393
Answer:
A. 32
Step-by-step explanation:
The relationship between segment lengths is ...
WT·WU = WC·WV
14(2x +2) = 12(2x +5)
28x +28 = 24x +60
4x = 32
2x = 16
Then the measure we're after is ...
UT = WT +WU = 14 +(16 +2)
UT = 32
Benchmark of 6/10, how do I get this worked out
Answer:
0.60 or 60% is the answer!
Step-by-step explanation:
Hope I helped
Maggie studied for 2/5 of an
hour. Julie studied for 1/4 of an
hour. How much longer did
Maggie study?
Answer: 3/20
Concept:
When encountering questions that ask for [how much longer A comparing to B], the basic operation would be the value of A subtracted by the value of B.
Solve:
Given information
Maggie study time = 2/5 hours
Julie study time = 1/4 hours
Given expression deducted from the concept
Maggie (study time) - Julie (study time)
Substitute values into the expression
2/5 - 1/4
Find the denominators' Least Common Multiple (LCM)
First five multiples of 5: 5, 10, 15, 20, 25
First five multiples of 4: 4, 8, 12, 16, 20
Since [20] is the first term that appears in both multiples, it would be the LCM of 4 and 5
Convert the fractions to common denominator
2/5 = (2 × 4) / (5 × 4) = 8 / 20
1/4 = (1 × 5) / (4 × 5) = 5 / 20
Simplify by subtraction
=8/20 - 5/20
=(8 - 5) / 20
=[tex]\boxed{\frac{3}{20} }[/tex]
Hope this helps!! :)
Please let me know if you have any questions
Which of the following is not a polynomial?
O A. 3x4
O B. x8+2x3 +7
O C. 5x10 - 4x8 + 2
O D. 5- x2 + 7x0
Answer:
C
Step-by-step explanation:
is not a polynomial because it has a negative exponent.
is a graph with asymptotes discontinious?
Answer:
In order for the function to be discontinuous at an asymptote, the curve needs to exist on both sides of the asymptote. If the curve only exists on one side of the asymptote, then there's no discontinuity at that point.
Step-by-step explanation:
