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goldfiish [28.3K]
3 years ago
14

What is the approximate uncertainty in the area of a circle of radius 3.1×104cm? Express your answer using one significant figur

e. ΔA =
Mathematics
1 answer:
Otrada [13]3 years ago
4 0
The area of a circle is expressed as:

Area = πr²
where r is the radius of the circle. This equation is used to calculate the area of the circle above. Calculation is as follows:

A = π(3.1 x 10^4 cm)² = 3.0 x 10^9 cm²

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Find the value of a and b if root3-1/root3+1+ root3+1/root3-1=a+root3 b​
Digiron [165]

Answer:

a=4 and b = 0

Step-by-step explanation:

Given : \dfrac{\sqrt 3 -1}{\sqrt 3+1}+\dfrac{\sqrt 3+1}{\sqrt 3-1}=a+\sqrt 3 b

To find, The value of a and b

Solution,

Solving LHS of the given equation,

\dfrac{(\sqrt 3-1)^2+(\sqrt3+1)^2}{(\sqrt 3+1)(\sqrt 3-1)}=a+\sqrt 3 b

Since,

(a-b)^2=a^2+b^2-2ab\\\\(a+b)^2=a^2+b^2+2ab\\\\(a-b)(a+b)=a^2+b^2

So,

\dfrac{3+1-2\sqrt 3+3+1+2\sqrt 3}{3-1}=a+\sqrt 3 b\\\\4=a+\sqrt 3 b

or

4+0=a+\sqrt 3 b

On comparing we get :

a = 4 and b = 0

4 0
3 years ago
How much more interest will Maria receive if she invests $1,000 for one year at x percent annual interest, compounded semiannual
notka56 [123]

Answer:

  $0.025x² . . . where x is a number of percentage points

Step-by-step explanation:

The multiplier for semi-annual compounding will be ...

  (1 + x/2)² = 1 + x + x²/4

The multiplier for annual compounding will be ...

  1 + x

The multiplier for semiannual compounding is greater by ...

  (1 + x + x²/4) - (1 + x) = x²/4

Maria's interest will be greater by $1000×(x²/4) = $250x², where x is a decimal fraction.

If x is a percent value, as in x = 6 when x percent = 6%, then the difference amount is ...

  $250·(x/100)² = $0.025x² . . . where x is a number of percentage points

_____

<u>Example</u>:

For x percent = 6%, the difference in interest earned on $1000 for one year is $0.025×6² = $0.90.

3 0
3 years ago
Zeina has seven times as many books as ali if zeina gave ali 15 books they would eash have the same number of books how many boo
ELEN [110]

Step-by-step explanation:

20 each because it's like tgat

5 0
3 years ago
3/7 of 8th graders play sports. is 3/5 of the 8th graders that play sports are boys, what fraction of the 8th graders are boys
Svetach [21]

Answer:

\dfrac{9}{35} is the fraction of 8th graders who are boys.

Step-by-step explanation:

Let total number of 8th graders = x

Given that, \frac{3}{7} of 8th graders play sports

\Rightarrow 8th graders who play sports = \frac{3}{7} \times x

Also, Given that, \frac{3}{5} of 8th graders that play sports are boys

Number of 8th graders that play sports, and are boys = \frac{3}{5} \times \text{Number of 8th graders who play sports}

\Rightarrow \dfrac{3}{5} \times \dfrac{3}{7} \times x\\\Rightarrow \dfrac{9}{35} \times x

Hence, the answer is:

\dfrac{9}{35} is the fraction of 8th graders who are boys.

6 0
2 years ago
1. f(x) = x2 - 21<br> f(5)
matrenka [14]

Answer:

x=13

Step-by-step explanation:

if you will substitute the value of f(x) with 5, you will get the following equation:

5=2x-21

2x=26/÷2

x=13

(I didn't know what you ment when you wrote x2, is it x square or 2X)

I really hope it was the second one, cause that's how I solved it.

8 0
3 years ago
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