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
ladessa [460]
3 years ago
7

Two numbers, 3 and a, have a geometric mean of 9. Find the value of a.

Mathematics
1 answer:
Ket [755]3 years ago
4 0
The geometric mean of two numbers x and y is √(xy).

So, if the geometric mean of 3 and a is 9 =>

9 = √(3a)

=> 9^2 = 3a

=> a = 9^2 / 3

a = 81 / 3

a = 27

Answer: the value of a is 27.
You might be interested in
Evaluate using integration by parts ​
PolarNik [594]

Rather than carrying out IBP several times, let's establish a more general result. Let

I(n)=\displaystyle\int x^ne^x\,\mathrm dx

One round of IBP, setting

u=x^n\implies\mathrm du=nx^{n-1}\,\mathrm dx

\mathrm dv=e^x\,\mathrm dx\implies v=e^x

gives

\displaystyle I(n)=x^ne^x-n\int x^{n-1}e^x\,\mathrm dx

I(n)=x^ne^x-nI(n-1)

This is called a power-reduction formula. We could try solving for I(n) explicitly, but no need. n=5 is small enough to just expand I(5) as much as we need to.

I(5)=x^5e^x-5I(4)

I(5)=x^5e^x-5(x^4e^x-4I(3))=(x-5)x^4e^x+20I(3)

I(5)=(x-5)x^4e^x+20(x^3e^x-3I(2))=(x^2-5x+20)x^3e^x-60I(2)

I(5)=(x^2-5x+20)x^3e^x-60(x^2e^x-2I(1))=(x^3-5x^2+20x-60)x^2e^x+120I(1)

I(5)=(x^3-5x^2+20x-60)x^2e^x+120(xe^x-I(0))

Finally,

I(0)=\displaystyle\int e^x\,\mathrm dx=e^x+C

so we end up with

I(5)=(x^4-5x^3+20x^2-60x+120)xe^x-120e^x+C

I(5)=(x^5-5x^4+20x^3-60x^2+120x-120)e^x+C

and the antiderivative is

\displaystyle\int2x^5e^x\,\mathrm dx=(2x^5-10x^4+40x^3-120x^2+240x-240)e^x+C

8 0
2 years ago
Really need help now!!
den301095 [7]

(20*6)+(12*6)+(18*10)=312 500-312=188 colored pencil's left.

4 0
3 years ago
Read 2 more answers
I need this as soon as possible
GaryK [48]

Answer:

123.94

Step-by-step explanation:

8 0
3 years ago
Fourth Quarter
Nina [5.8K]

Answer:

A.

Step-by-step explanation:

playing in the garden

7 0
3 years ago
Solve the inequality
exis [7]
N<6  is the answer I think

3 0
3 years ago
Read 2 more answers
Other questions:
  • I need help with this question
    14·1 answer
  • Point D(-1, 5) is reflected across the x-axis. Which statements about D' are true?
    6·1 answer
  • Two friends play a game to see if one can spot the true statements when the other gives them a list of truths and lies mixed tog
    8·1 answer
  • HELP ASAP 25 POINTS WILL MARK CORRECT ANSWER BRAINLIEST
    8·1 answer
  • *Help needed*
    14·2 answers
  • Classify the triangle by its sides that measure 10, 4, and 10 inches
    7·1 answer
  • On an electricity bill of $40.80, Mrs.
    11·2 answers
  • Please help i'll give brainliest
    6·2 answers
  • Some friends spent the afternoon collecting aluminum cans for
    9·2 answers
  • What is X equal to? <br> Urgent! Middle school work
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!