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
Murljashka [212]
2 years ago
7

Solve only if you know the solution and show work.

Mathematics
1 answer:
SashulF [63]2 years ago
5 0
\displaystyle\int\frac{\cos x+3\sin x+7}{\cos x+\sin x+1}\,\mathrm dx=\int\mathrm dx+2\int\frac{\sin x+3}{\cos x+\sin x+1}\,\mathrm dx

For the remaining integral, let t=\tan\dfrac x2. Then

\sin x=\sin\left(2\times\dfrac x2\right)=2\sin\dfrac x2\cos\dfrac x2=\dfrac{2t}{1+t^2}
\cos x=\cos\left(2\times\dfrac x2\right)=\cos^2\dfrac x2-\sin^2\dfrac x2=\dfrac{1-t^2}{1+t^2}

and

\mathrm dt=\dfrac12\sec^2\dfrac x2\,\mathrm dx\implies \mathrm dx=2\cos^2\dfrac x2\,\mathrm dt=\dfrac2{1+t^2}\,\mathrm dt

Now the integral is

\displaystyle\int\mathrm dx+2\int\frac{\dfrac{2t}{1+t^2}+3}{\dfrac{1-t^2}{1+t^2}+\dfrac{2t}{1+t^2}+1}\times\frac2{1+t^2}\,\mathrm dt

The first integral is trivial, so we'll focus on the latter one. You have

\displaystyle2\int\frac{2t+3(1+t^2)}{(1-t^2+2t+1+t^2)(1+t^2)}\,\mathrm dt=2\int\frac{3t^2+2t+3}{(1+t)(1+t^2)}\,\mathrm dt

Decompose the integrand into partial fractions:

\dfrac{3t^2+2t+3}{(1+t)(1+t^2)}=\dfrac2{1+t}+\dfrac{1+t}{1+t^2}

so you have

\displaystyle2\int\frac{3t^2+2t+3}{(1+t)(1+t^2)}\,\mathrm dt=4\int\frac{\mathrm dt}{1+t}+2\int\frac{\mathrm dt}{1+t^2}+\int\frac{2t}{1+t^2}\,\mathrm dt

which are all standard integrals. You end up with

\displaystyle\int\mathrm dx+4\int\frac{\mathrm dt}{1+t}+2\int\frac{\mathrm dt}{1+t^2}+\int\frac{2t}{1+t^2}\,\mathrm dt
=x+4\ln|1+t|+2\arctan t+\ln(1+t^2)+C
=x+4\ln\left|1+\tan\dfrac x2\right|+2\arctan\left(\arctan\dfrac x2\right)+\ln\left(1+\tan^2\dfrac x2\right)+C
=2x+4\ln\left|1+\tan\dfrac x2\right|+\ln\left(\sec^2\dfrac x2\right)+C

To try to get the terms to match up with the available answers, let's add and subtract \ln\left|1+\tan\dfrac x2\right| to get

2x+5\ln\left|1+\tan\dfrac x2\right|+\ln\left(\sec^2\dfrac x2\right)-\ln\left|1+\tan\dfrac x2\right|+C
2x+5\ln\left|1+\tan\dfrac x2\right|+\ln\left|\dfrac{\sec^2\dfrac x2}{1+\tan\dfrac x2}\right|+C

which suggests A may be the answer. To make sure this is the case, show that

\dfrac{\sec^2\dfrac x2}{1+\tan\dfrac x2}=\sin x+\cos x+1

You have

\dfrac{\sec^2\dfrac x2}{1+\tan\dfrac x2}=\dfrac1{\cos^2\dfrac x2+\sin\dfrac x2\cos\dfrac x2}
\dfrac{\sec^2\dfrac x2}{1+\tan\dfrac x2}=\dfrac1{\dfrac{1+\cos x}2+\dfrac{\sin x}2}
\dfrac{\sec^2\dfrac x2}{1+\tan\dfrac x2}=\dfrac2{\cos x+\sin x+1}

So in the corresponding term of the antiderivative, you get

\ln\left|\dfrac{\sec^2\dfrac x2}{1+\tan\dfrac x2}\right|=\ln\left|\dfrac2{\cos x+\sin x+1}\right|
=\ln2-\ln|\cos x+\sin x+1|

The \ln2 term gets absorbed into the general constant, and so the antiderivative is indeed given by A,

\displaystyle\int\frac{\cos x+3\sin x+7}{\cos x+\sin x+1}\,\mathrm dx=2x+5\ln\left|1+\tan\dfrac x2\right|-\ln|\cos x+\sin x+1|+C
You might be interested in
PLEASE HEEEEEEEEEEEEEEEEEELP
inna [77]
I’m pretty sure it’s 3 and a 2
8 0
3 years ago
What is the dilation for the transformation below?​
lys-0071 [83]

Answer:

The dialation is of 2

Step-by-step explanation:

QR = 3 units

QS = 2 units

RS = 2 units

Q'R' = 6 units

Q'S' = 4 units

R'S' = 4 units

So as you can see, this triangle has doubled it's size, since it has been multiplied by 2.

Hope this helped!

Have a supercalifragilisticexpialidocious day!

4 0
2 years ago
A sheet of origami paper is in the shape of a square with a side length of 7 inches, as shown. What is the area of the sheet of
vlabodo [156]
??... what lol good job tho
8 0
2 years ago
Read 2 more answers
Determine the point and the slope y - 5 = -4(x + 1)
Rashid [163]

Answer:

slope = -4, y intercept = 1

Step-by-step explanation:

7 0
2 years ago
a cookie recipe yields 48 cookies calls for 2 cups of flour. a different cookie recipe yield 60 cookies calls for 3 cups. Are th
fenix001 [56]
No they are not.
48/2 = 24, 60/3=20.
24/=20. (24 does not equal 20)
6 0
3 years ago
Read 2 more answers
Other questions:
  • Jacob has 16 toy cars. 3/8 of the cars are red and the rest are blue. How many cars are blue.
    11·1 answer
  • Which equation represents a line with a greater slope and lesser y intercept than the line shown?
    10·1 answer
  • If it is possible...<br> What two numbers added is 4 and multiplied to be 7?
    11·2 answers
  • There is a 85% probability that Jack's dad gives him permission to go to the movies tonight. There is a 60% chance that he will
    9·1 answer
  • pam walks 7/8 of a mile to school paul walks 1/2 of a mile to school how much farther does pam walk than paul
    13·2 answers
  • What are the possible side lengths of a triangle
    9·2 answers
  • I have a spinner that is divided into 4 equal sections colored red, blue, green, and yellow .If I spin the spinner twice ,What i
    15·2 answers
  • !00000 times 62<br> Go sub to my bros yt keditoplayz
    8·2 answers
  • Adsila's recipe for peach frozen yogurt says to mix 3 cups blended peaches for every 2 cups vanilla yogurt. Which of these froze
    11·1 answer
  • 3. Michelle wants to save at least $3,500. She has already put away
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!