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3 years ago

How do you find the area of a circle with just the radius?

Mathematics

2 answers:

zloy xaker [14]3 years ago

5 0

Answer:

Oh that's easy! You find out what the radius is.. then the diameter is another one of that number. Example say that the radius is 10 then the diameter is 20 or if the radius is 7 the diameter is 14

Step-by-step explanation:

WINSTONCH [101]3 years ago

5 0

Answer:

<h2>Use the formula A = π(r²) where r is the radius</h2>

Step-by-step explanation:

π = pi, and r is the radius. It's the only value you need to find the area of a circle. π is usually represented as 3.14, or you can use the π button on your calculator

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For the function below, find a formula for the upper sum obtained by dividing the interval [a comma b ][a,b] into n equal subin

Vlad [161]

Answer:

See below

Step-by-step explanation:

We start by dividing the interval [0,4] into n sub-intervals of length 4/n

$[0,\displaystyle\frac{4}{n}],[\displaystyle\frac{4}{n},\displaystyle\frac{2*4}{n}],[\displaystyle\frac{2*4}{n},\displaystyle\frac{3*4}{n}],...,[\displaystyle\frac{(n-1)*4}{n},4]$

Since f is increasing in the interval [0,4], the upper sum is obtained by evaluating f at the right end of each sub-interval multiplied by 4/n.

Geometrically, these are the areas of the rectangles whose height is f evaluated at the right end of the interval and base 4/n (see picture)

$\displaystyle\frac{4}{n}f(\displaystyle\frac{1*4}{n})+\displaystyle\frac{4}{n}f(\displaystyle\frac{2*4}{n})+...+\displaystyle\frac{4}{n}f(\displaystyle\frac{n*4}{n})=\\\\=\displaystyle\frac{4}{n}((\displaystyle\frac{1*4}{n})^2+3+(\displaystyle\frac{2*4}{n})^2+3+...+(\displaystyle\frac{n*4}{n})^2+3)=\\\\\displaystyle\frac{4}{n}((1^2+2^2+...+n^2)\displaystyle\frac{4^2}{n^2}+3n)=\\\\\displaystyle\frac{4^3}{n^3}(1^2+2^2+...+n^2)+12$

but

$1^2+2^2+...+n^2=\displaystyle\frac{n(n+1)(2n+1)}{6}$

so the upper sum equals

$\displaystyle\frac{4^3}{n^3}(1^2+2^2+...+n^2)+12=\displaystyle\frac{4^3}{n^3}\displaystyle\frac{n(n+1)(2n+1)}{6}+12=\\\\\displaystyle\frac{4^3}{6}(2+\displaystyle\frac{3}{n}+\displaystyle\frac{1}{n^2})+12$

When $n\rightarrow \infty$ both $\displaystyle\frac{3}{n}$ and $\displaystyle\frac{1}{n^2}$ tend to zero and the upper sum tends to

$\displaystyle\frac{4^3}{3}+12=\displaystyle\frac{100}{3}$

8 0

4 years ago

HELP ASAP!! Two customers took out loans from a bank. • Henry took out a 4-year loan for $5,000 and paid 4.2% annual simple inte

guajiro [1.7K]

Answer:

Step-by-step explanation:

4.2 precent of 5000 is 210. You multiply that by the year (4) because he paid 4.2 of 5000 anually. If you multiply that the answer should be 840.

3.9 precent of 5000 is 195. If you multiply that again by 6 (the year) because he paid 3.9 of 5000 anually. If you multiply that your answer should be 1170.

Now after all that subtract. 1170-840= 330

3 0

3 years ago

Read 2 more answers

5 * 3/5 i need help please

kompoz [17]

Answer:

Step-by-step explanation:

Order of operations.

5*3/5 is basically the same as 5 times 3 divided by 5. If you are multiplying 5 by 3, and then dividing that same number from the answer, which is 5, then you will get the same number you multiplied by, or 3.

6 0

4 years ago

Raportul a doua catete ale unui triunghi dreptunghic este de 3 supra 7,iar inaltimea este de 42cm.Aflati inaltimea,catetele,ipot

Basile [38]

Answer:

could you write in in english

Step-by-step explanation:

6 0

3 years ago

Find the inverse of f(x) = 1/2x + 3

vodka [1.7K]

The equation we have right now is basically y = 1/2x + 3. We can switch the x and y variables. Our new equation is: x = 1/2y + 3. Next, we solve for y.

Firstly, we subtract 3 from both sides. This gives us x - 3 = 1/2y. Next, we multiply both sides by 2 to isolate y. This gives us 2(x - 3) = 1/2y. Then, we have 2x - 6 = y.

The answer is f(x) = 2x - 6

3 0

3 years ago