1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
mina [271]
1 year ago
10

Calculus 3 help please.​

Mathematics
1 answer:
Reptile [31]1 year ago
8 0

I assume each path C is oriented positively/counterclockwise.

(a) Parameterize C by

\begin{cases} x(t) = 4\cos(t) \\ y(t) = 4\sin(t)\end{cases} \implies \begin{cases} x'(t) = -4\sin(t) \\ y'(t) = 4\cos(t) \end{cases}

with -\frac\pi2\le t\le\frac\pi2. Then the line element is

ds = \sqrt{x'(t)^2 + y'(t)^2} \, dt = \sqrt{16(\sin^2(t)+\cos^2(t))} \, dt = 4\,dt

and the integral reduces to

\displaystyle \int_C xy^4 \, ds = \int_{-\pi/2}^{\pi/2} (4\cos(t)) (4\sin(t))^4 (4\,dt) = 4^6 \int_{-\pi/2}^{\pi/2} \cos(t) \sin^4(t) \, dt

The integrand is symmetric about t=0, so

\displaystyle 4^6 \int_{-\pi/2}^{\pi/2} \cos(t) \sin^4(t) \, dt = 2^{13} \int_0^{\pi/2} \cos(t) \sin^4(t) \,dt

Substitute u=\sin(t) and du=\cos(t)\,dt. Then we get

\displaystyle 2^{13} \int_0^{\pi/2} \cos(t) \sin^4(t) \, dt = 2^{13} \int_0^1 u^4 \, du = \frac{2^{13}}5 (1^5 - 0^5) = \boxed{\frac{8192}5}

(b) Parameterize C by

\begin{cases} x(t) = 2(1-t) + 5t = 3t - 2 \\ y(t) = 0(1-t) + 4t = 4t \end{cases} \implies \begin{cases} x'(t) = 3 \\ y'(t) = 4 \end{cases}

with 0\le t\le1. Then

ds = \sqrt{3^2+4^2} \, dt = 5\,dt

and

\displaystyle \int_C x e^y \, ds = \int_0^1 (3t-2) e^{4t} (5\,dt) = 5 \int_0^1 (3t - 2) e^{4t} \, dt

Integrate by parts with

u = 3t-2 \implies du = 3\,dt \\\\ dv = e^{4t} \, dt \implies v = \frac14 e^{4t}

\displaystyle \int u\,dv = uv - \int v\,du

\implies \displaystyle 5 \int_0^1 (3t-2) e^{4t} \,dt = \frac54 (3t-2) e^{4t} \bigg|_{t=0}^{t=1} - \frac{15}4 \int_0^1 e^{4t} \,dt \\\\ ~~~~~~~~ = \frac54 (e^4 + 2) - \frac{15}{16} e^{4t} \bigg|_{t=0}^{t=1} \\\\ ~~~~~~~~ = \frac54 (e^4 + 2) - \frac{15}{16} (e^4 - 1) = \boxed{\frac{5e^4 + 55}{16}}

(c) Parameterize C by

\begin{cases} x(t) = 3(1-t)+t = -2t+3 \\ y(t) = (1-t)+2t = t+1 \\ z(t) = 2(1-t)+5t = 3t+2 \end{cases} \implies \begin{cases} x'(t) = -2 \\ y'(t) = 1 \\ z'(t) = 3 \end{cases}

with 0\le t\le1. Then

ds = \sqrt{(-2)^2 + 1^2 + 3^2} \, dt = \sqrt{14} \, dt

and

\displaystyle \int_C y^2 z \, ds = \int_0^1 (t+1)^2 (3t+2) \left(\sqrt{14}\,ds\right) \\\\ ~~~~~~~~ = \sqrt{14} \int_0^1 \left(3t^3 + 8t^2 + 7t + 2\right) \, dt \\\\ ~~~~~~~~ = \sqrt{14} \left(\frac34 t^4 + \frac83 t^3 + \frac72 t^2 + 2t\right) \bigg|_{t=0}^{t=1} \\\\ ~~~~~~~~ = \sqrt{14} \left(\frac34 + \frac83 + \frac72 + 2\right) = \boxed{\frac{107\sqrt{14}}{12}}

You might be interested in
Can anybody help me with these?
skelet666 [1.2K]

Answer:

Which One ?

Step-by-step explanation:

8 0
3 years ago
How is it going to tell me the answer
Anon25 [30]
I dont know man you gotta ask a question
7 0
3 years ago
Find the exact value of sin G
ad-work [718]
We need to find the value of the hypotenuse in order to solve this problem.

12^2+4^2=H^2

Therefore:

H=√(144+16)

H=4√10

Now:

sin(G)=O/H=4/(4√10)

=1/(√10)

=(√10)/10
6 0
3 years ago
I am trying to remember how to do Write a two-column proof,
Klio2033 [76]

9514 1404 393

Explanation:

Make use of the properties of equality.

  a = 2b +6 . . . . . given

  a = 9b -8 . . . . . given

  2b +6 = 9b -8 . . . . . . . substitution property of equality

  6 = 7b -8 . . . . . . . . . . . subtraction property of equality

  14 = 7b . . . . . . . . . . . . . addition property of equality

  2 = b . . . . . . . . . . . . . . . division property of equality

  b = 2 . . . . . . . . . . . . . . symmetric property of equality

4 0
3 years ago
Alim buys 2 t-shirts for $9.50 each, a 3-pack of socks for $7.95, and a pair of shoes for $7.95 and a pair of shoes for $49.95.
Usimov [2.4K]
First, I add all of my prices together.
$9.50(2)+$7.95+$7.95+$49.95= $84.85
Change 6% to a decimal = .06
Then multiply: 84.85 x .06 =  $5.09
$5.09 is the sales tax
$84.85 + $5.09 = $89.94

Answer: $89.94
I hope this helps :)
3 0
3 years ago
Other questions:
  • Using diaries for many weeks, a study on the lifestyles of visually impaired students was conducted. the students kept track of
    10·1 answer
  • Evaluate each expression.<br> 1. 56/b for b=7<br> 2. v+16 for v=9<br> 3.2(4e) for e=5
    9·1 answer
  • Which graph models the function f(x) = −2(3)x?
    14·1 answer
  • I'm not sure how to do this, help?
    5·1 answer
  • Someone answer 1-8 please! (Please do help!)<br> QUESTION: Find each quotient.
    9·1 answer
  • Factor the polynomial using the pattern x^2+9x+18
    11·2 answers
  • 19. Fill in the numbers to find the100
    5·2 answers
  • Plz help me out! :)<br><br><br> 62 is 50% of what number?
    14·1 answer
  • Make g the subject of the formula w=7-g
    7·1 answer
  • Số táo của An, Bình, Chi là như nhau. An cho đi 17 quả , Chi cho đi 19 quả thì lúc này số táo của Chi gấp 5 lần tổng số táo còn
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!