How do I evaluate this using trigonometric substitution?
∫dx/(81x^2+4)^2
Answer:
[tex]\displaystyle \frac{1}{144}arctan(\frac{9x}{2}) + \frac{x}{8(81x^2 + 4)} + C[/tex]
General Formulas and Concepts:
Alg I
Terms/CoefficientsFactorExponential Rule [Dividing]: [tex]\displaystyle \frac{b^m}{b^n} = b^{m - n}[/tex]Pre-Calc
[Right Triangle Only] Pythagorean Theorem: a² + b² = c²
a is a legb is a legc is hypotenuseTrigonometric Ratio: [tex]\displaystyle sec(\theta) = \frac{1}{cos(\theta)}[/tex]
Trigonometric Identity: [tex]\displaystyle tan^2\theta + 1 = sec^2\theta[/tex]
TI: [tex]\displaystyle sin(2x) = 2sin(x)cos(x)[/tex]
TI: [tex]\displaystyle cos^2(\theta) = \frac{cos(2x) + 1}{2}[/tex]
Calc
Integration Rule [Reverse Power Rule]: [tex]\displaystyle \int {x^n} \, dx = \frac{x^{n + 1}}{n + 1} + C[/tex]
Integration Property [Multiplied Constant]: [tex]\displaystyle \int {cf(x)} \, dx = c \int {f(x)} \, dx[/tex]
IP [Addition/Subtraction]: [tex]\displaystyle \int {[f(x) \pm g(x)]} \, dx = \int {f(x)} \, dx \pm \int {g(x)} \, dx[/tex]
U-Substitution
U-Trig Substitution: x² + a² → x = atanθ
Step-by-step explanation:
Step 1: Define
[tex]\displaystyle \int {\frac{dx}{(81x^2 + 4)^2}}[/tex]
Step 2: Identify Sub Variables Pt.1
Rewrite integral [factor expression]:
[tex]\displaystyle \int {\frac{dx}{[(9x)^2 + 4]^2}}[/tex]
Identify u-trig sub:
[tex]\displaystyle x = atan\theta\\9x = 2tan\theta \rightarrow x = \frac{2}{9}tan\theta\\dx = \frac{2}{9}sec^2\theta d\theta[/tex]
Later, back-sub θ (integrate w/ respect to x):
[tex]\displaystyle tan\theta = \frac{9x}{2} \rightarrow \theta = arctan(\frac{9x}{2})[/tex]
Step 3: Integrate Pt.1
[Int] Sub u-trig variables: [tex]\displaystyle \int {\frac{\frac{2}{9}sec^2\theta}{[(2tan\theta)^2 + 4]^2}} \ d\theta[/tex][Int] Rewrite [Int Prop - MC]: [tex]\displaystyle \frac{2}{9} \int {\frac{sec^2\theta}{[(2tan\theta)^2 + 4]^2}} \ d\theta[/tex][Int] Evaluate exponents: [tex]\displaystyle \frac{2}{9} \int {\frac{sec^2\theta}{[4tan^2\theta + 4]^2}} \ d\theta[/tex][Int] Factor: [tex]\displaystyle \frac{2}{9} \int {\frac{sec^2\theta}{[4(tan^2\theta + 1)]^2}} \ d\theta[/tex][Int] Rewrite [TI]: [tex]\displaystyle \frac{2}{9} \int {\frac{sec^2\theta}{[4sec^2\theta]^2}} \ d\theta[/tex][Int] Evaluate exponents: [tex]\displaystyle \frac{2}{9} \int {\frac{sec^2\theta}{16sec^4\theta} \ d\theta[/tex][Int] Rewrite [Int Prop - MC]: [tex]\displaystyle \frac{1}{72} \int {\frac{sec^2\theta}{sec^4\theta} \ d\theta[/tex][Int] Divide [ER - D]: [tex]\displaystyle \frac{1}{72} \int {\frac{1}{sec^2\theta} \ d\theta[/tex][Int] Rewrite [TR]: [tex]\displaystyle \frac{1}{72} \int {cos^2\theta} \ d\theta[/tex][Int] Rewrite [TI]: [tex]\displaystyle \frac{1}{72} \int {\frac{cos(2\theta) + 1}{2}} \ d\theta[/tex][Int] Rewrite [Int Prop - MC]: [tex]\displaystyle \frac{1}{144} \int {cos(2\theta) + 1} \ d\theta[/tex][Int] Rewrite [Int Prop - A/S]: [tex]\displaystyle \frac{1}{144} [\int {cos(2\theta) \ d\theta + \int {1} \ d\theta][/tex]Step 4: Identify Sub Variables Pt.2
Determine u-sub for trig int:
u = 2θ
du = 2dθ
Step 5: Integrate Pt.2
[Ints] Rewrite [Int Prop - MC]: [tex]\displaystyle \frac{1}{144} [\frac{1}{2} \int {2cos(2\theta) \ d\theta + \int {1 \theta ^0} \ d\theta][/tex][Int] U-Sub: [tex]\displaystyle \frac{1}{144} [\frac{1}{2} \int {cos(u) \ du + \int {1 \theta ^0} \ d\theta][/tex][Ints] Integrate [Trig/Int Rule - RPR]: [tex]\displaystyle \frac{1}{144} [\frac{1}{2} sin(u) + \theta + C][/tex][Expression] Back Sub: [tex]\displaystyle \frac{1}{144} [\frac{1}{2} sin(2 \theta) + arctan(\frac{9x}{2}) + C][/tex][Exp] Rewrite [TI]: [tex]\displaystyle \frac{1}{144} [\frac{1}{2}(2sin(\theta)cos(\theta)) + arctan(\frac{9x}{2}) + C][/tex][Exp] Multiply: [tex]\displaystyle \frac{1}{144} [sin(\theta)cos(\theta) + arctan(\frac{9x}{2}) + C][/tex][Exp] Back Sub: [tex]\displaystyle \frac{1}{144} [sin(arctan(\frac{9x}{2}))cos(arctan(\frac{9x}{2})) + arctan(\frac{9x}{2}) + C][/tex]Step 6: Triangle
Find trig values:
[tex]\displaystyle tan\theta = \frac{9x}{2}[/tex]
[tex]\displaystyle \theta = arctan(\frac{9x}{2})[/tex]
tanθ = opposite / adjacent; solve hypotenuse of right triangle, determine trig ratios:
sinθ = opposite / hypotenuse
cosθ = adjacent / hypotenuse
Leg a = 2
Leg b = 9x
Leg c = ?
Sub variables [PT]: [tex]\displaystyle 2^2 + (9x)^2 = c^2[/tex]Evaluate exponents: [tex]\displaystyle 4 + 81x^2 = c^2[/tex][Equality Property] Square root both sides: [tex]\displaystyle \sqrt{4 + 81x^2} = c[/tex]Rewrite: [tex]c = \sqrt{81x^2 + 4}[/tex]Substitute into trig ratios:
[tex]\displaystyle sin\theta = \frac{9x}{\sqrt{81x^2 + 4}}[/tex]
[tex]\displaystyle cos\theta = \frac{2}{\sqrt{81x^2 + 4}}[/tex]
Step 7: Integrate Pt.3
[Exp] Sub variables [TR]: [tex]\displaystyle \frac{1}{144} [\frac{9x}{\sqrt{81x^2 + 4}} \cdot \frac{2}{\sqrt{81x^2 + 4}} + arctan(\frac{9x}{2}) + C][/tex][Exp] Multiply: [tex]\displaystyle \frac{1}{144} [\frac{18x}{81x^2 + 4} + arctan(\frac{9x}{2}) + C][/tex][Exp] Distribute: [tex]\displaystyle \frac{1}{144}arctan(\frac{9x}{2}) + \frac{x}{8(81x^2 + 4)} + C[/tex]A pair of shoes that originally sold at $30 is now being offered at a 25% discount.
What is its present price?
Answer:
$22.5
Step-by-step explanation:
You will pay $22.5 for a item with original price of $30 when discounted 25%.
Answer:
Refer to explanation
Step-by-step explanation:
The screenshot you put is the correct answer, here's another method to get the same answer:
Find what 25% is.
100% = 30
1% = 30 ÷ 100 = 0.30
25% = 0.30 x 25 = 7.50
Find the price after the 25% discount.
100 - 25 = 75
75% = 30 - 7.50 = 22.50 or 0.30 x 75 = 22.50 (Both solutions give the same answer)
At Davidson's Bike Rentals, it costs $41 to rent a bike for 8 hours. How many hours of bike use does a customer get per dollar?
Answer:
0.192 hour
Step-by-step explanation:
41$ / 8 = 0.192 hours = 11.703 minutes
What is - or how do you find answer to:
12 1/2 - (-4 1/2) =
Answer:
8
Step-by-step explanation:
12 times 1/2=6
(-4(1/2))= -2
6-(-2)
6+2
=8
A 12-pack of soda costs $10.08 and a 6-pack of the same soda cost $5.34. Which is
the better buy?
Answer:
the twelve pack
Step-by-step explanation:
12 pack = $10.08 if u get the 6 pack for $5.34 and want to buy two pack it equals $10.68 if you want to save change buy the 12 pack
How many grams of aluminum hydroxide are produced when 8 moles of aluminum sulfite react in excess sodium hydroxide ?
Answer:
Number of moles Aluminium sulfide
1 mole of sulfide contains 150 g
Therefore; 16.2/150
= 0.108 moles
The mole ratio of Al2S3 : Al(OH)3 is 1:2
Therefore; moles of Aluminium hydroxide will be;
= (0.108 × 2)
= 0.216 moles
But, 1 mole of Al(OH)3 contains 77 g
Therefore, the mass of aluminium hydroxide is
0.216 moles × 77
= 16.632 g
Step-by-step explanation:
5 × 3/2, but the answer as a fraction
Answer:
15/2
Step-by-step explanation:
5/1 * 3/2 = 15/2
Math please help ASAP
Answer:
11
Step-by-step explanation:
i don't know
A plane travels 1820 meters at a speed of 260 m/sec. How long did it
take to reach its destination? PLEASE HELP!
Answer:
7 seconds
Step-by-step explanation:
1820/260=7.
Answer:
7m/sec
Step-by-step explanation:
Tyler has $125.00 to spend on books and CDs. He buys one book for $30.00. He wants to spend the rest on CDs that are on sale for $9.00 each. Which of these statements is true?
Group of answer choices
He can't buy any CDs.
He can buy 11 CDs.
He can buy 10 CDs.
He can buy more than 11 CDs.
Answer:
He can buy 10 cds
Step-by-step explanation:
125-30=95
95 divided by 9 = 10.5555555556
Pls help I’ll mark brainliest
Answer:
2=72 4=148 6=222 10=370 15=555 16=592
sorry about the second part i didnt see it
Answer:
148, 3 , 740, 1110, 8.
Step-by-step explanation:
Miles: 148 + 740 + 1,110 = 1,998
Gallons: 2 + 4 + 3 + 10 + 15 + 8 = 42
solve for x
8x+12=48-3(x+1)
Answer:
hello! :) have a good day!
X = 3
the area of a certain desert is nine times the area of another desert. if the sum of their areas is 30,000,000 sq miles. find the area of each.
The perimeter of the first rectangle below is 120 inches. The perimeter of the second rectangle is 180 inches. What are the values of x and v?
A. x = 6; v = 42
B. x = 13; v = 42
C. x = 42; v = 6
D. x = 48; v = 28
Answer:
A
Step-by-step explanation:
Answer:
A. x = 6; v = 42
Step-by-step explanation:
Strategy : Guess and Check
Let's start with A:
If x = 6, then the first rectangle would be 12 + 42 + 6 + 12 + 42 + 6 = 120
Let's see if this checks out with the second rectangle.
6 + 42 + 42 + 6 + 42 + 42 = 180
12
A model maker wants to make a model of a
ship
He will use a scale of 1:50
The ship was 100ft long
1 foot = 0.3 m
How long will the ship be in cm?
9514 1404 393
Answer:
60 cm
Step-by-step explanation:
The model ship will be x feet long, where ...
x/100 = 1/50
x = 100/50 = 2
In meters, that is ...
2(0.3 m) = 0.6 m
A meter is 100 cm, so the length in centimeters is ...
(0.6)(100 cm) = 60 cm
What quadrilateral's diagonals are perpendicular and they bisect each other?
Answer:
Rhombus
Step-by-step explanation:
The diagonals of Rhombus bisect each other and form 4 right triangles. Since they are right triangles, they measure 90 degrees so the diagonals are perpendicular.
Paisley works on her drawings for 2 hours. She spends 1/6 hour on each drawing. How many drawings does she work on in 2 hours? HELP FAST!!!!
Answer:
1/12
Step-by-step explanation:
1/6 divided by 2 = 1/12
To make concrete Tyler mixes 55 kilograms of gravel wit 11 kilograms of cement how many kilograms of gravel does Tyler need for each kilogram of cement
Answer:
5 kilos
Step-by-step explanation:
55:11
5:1 ratio
What's the place value of 3 in 19.364?
Answer:
Tenths
Hope this helps :)
Answer:
tenths
Step-by-step explanation:
List three decimal values between 2.5 and 2.6
Answer:
2.55 2.56 2.57
Step-by-step explanation:
Answer:
2.51, 2.52, 2.59
Step-by-step explanation:
Ay yo whats good bro
⦣G and ⦣H are complementary. If the measure of ⦣H is 72°, what is the measure of ⦣G?
9514 1404 393
Answer:
∠G = 18°
Step-by-step explanation:
Complementary angles total 90°. The measure of G is ...
∠G = 90° -72° = 18°
The perimeter of a rectangular e room is 24 feet. Twice the length
decreased by three times the width is 4 feet. What are the dimensions e of
thg room?
Please help me
Answer:
i am gessing to divide
Step-by-step explanation:
1. -3(-2-4-0)+3-(3-5-7)=
Answer: The answer is 18
Answer:
[tex] - 3 + 5 + 7 - 18 + 36 \\ - 3 + 12 - 18 + 36 \\ - 21 + 36 \\ = 15 \: \: \: ans.[/tex]
URGENT NEED ANSWERS •_•
X/4-5>-4 what is this please help
Answer:
4
Step-by-step explanation:
44 yeah yeah what about the other
write in exponential notation (-3)^6/ (-3)
Answer:
-3⁵
Step-by-step explanation:
3⁶ / -3 = -3⁶ * -3⁻¹ = -3⁶⁻¹ = -3⁵
Answer:
(-3)⁶/(-3) = {(-3)×(-3)×(-3)×(-3)×(-3)×(-3)}/(-3) = (-3)⁵
-3⁵ is the right answer.please help me please
Answer:
It won't let me see the picture
Step-by-step explanation:
A mistake was made in the steps shown to simplify the expression. Which step includes the mistake?
9/2+ 3(4 – 1) – 7 + 23
Step 1: = 9/2+ 3(3) — 7 + 23
Step 2: = 9/2 + 3(3) - 7 + 8
Step 3: =15/2 (3) — 7+8
Step 4: =45/2 - 7+8
Step 5: =31/2 +8
Step 6: =47/2
Answer: step 3 maybe?
Step-by-step explanation:
A white-tailed deer is running from a black bear at 20 miles per hour. It is 1/3 miles in front of the bear. The bear is running at 30 miles per hour. How many minutes will it take the bear to catch the deer? Assume both continue running at a constant pace.
Answer:
Step-by-step explanation:
d=20t+1/3, b=30t
20t+1/3=30t
10t=1/3
t=1/30 hr
t=(1/30)60=2 min
PLS HELP!!!! :))) BDHDHSJWJDJD
Answer:
Your answer is "H"
Step-by-step explanation:
