All categories

3 years ago

I NEED AN ANSWER PLEASE!

Mathematics

1 answer:

Nata [24]3 years ago

7 0

Answer:

1×-5= -5squared =25+(4×-4squared)=25+(-16)=9

You might be interested in

<img src="https://tex.z-dn.net/?f=%24a%2Ba%20r%2Ba%20r%5E%7B2%7D%2B%5Cldots%20%5Cinfty%3D15%24%24a%5E%7B2%7D%2B%28a%20r%29%5E%7B

riadik2000 [5.3K]

Let

$S_n = \displaystyle \sum_{k=0}^n r^k = 1 + r + r^2 + \cdots + r^n$

where we assume |r| < 1. Multiplying on both sides by r gives

$r S_n = \displaystyle \sum_{k=0}^n r^{k+1} = r + r^2 + r^3 + \cdots + r^{n+1}$

and subtracting this from $S_n$ gives

$(1 - r) S_n = 1 - r^{n+1} \implies S_n = \dfrac{1 - r^{n+1}}{1 - r}$

As n → ∞, the exponential term will converge to 0, and the partial sums $S_n$ will converge to

$\displaystyle \lim_{n\to\infty} S_n = \dfrac1{1-r}$

Now, we're given

$a + ar + ar^2 + \cdots = 15 \implies 1 + r + r^2 + \cdots = \dfrac{15}a$

$a^2 + a^2r^2 + a^2r^4 + \cdots = 150 \implies 1 + r^2 + r^4 + \cdots = \dfrac{150}{a^2}$

We must have |r| < 1 since both sums converge, so

$\dfrac{15}a = \dfrac1{1-r}$

$\dfrac{150}{a^2} = \dfrac1{1-r^2}$

Solving for r by substitution, we have

$\dfrac{15}a = \dfrac1{1-r} \implies a = 15(1-r)$

$\dfrac{150}{225(1-r)^2} = \dfrac1{1-r^2}$

Recalling the difference of squares identity, we have

$\dfrac2{3(1-r)^2} = \dfrac1{(1-r)(1+r)}$

We've already confirmed r ≠ 1, so we can simplify this to

$\dfrac2{3(1-r)} = \dfrac1{1+r} \implies \dfrac{1-r}{1+r} = \dfrac23 \implies r = \dfrac15$

It follows that

$\dfrac a{1-r} = \dfrac a{1-\frac15} = 15 \implies a = 12$

and so the sum we want is

$ar^3 + ar^4 + ar^6 + \cdots = 15 - a - ar - ar^2 = \boxed{\dfrac3{25}}$

which doesn't appear to be either of the given answer choices. Are you sure there isn't a typo somewhere?

7 0

3 years ago

A line passes through (3, 7) and (6, 9). Which equation best represents the line? (4 points) y = 3 over 2 x + 5 y = 2 over 3 x +

kotykmax [81]

Given two points, the equation of the line may be determined by,

y - y1 = ((y2 - y1) / (x2 - x1))(x - x1)

Substituting the given values,

y - 7 = ((9 - 7) / (6 - 3))(x - 3)

Simplification will yield to an answer of,

y = 2x/3 +5

Therefore, the answer is the second choice.

8 0

3 years ago

Pls help me solve pls show how you got the answer

jeyben [28]

Answer:

Step-by-step explanation:

p=8 cm

one side=8/4=2 cm

edge of black square=2/4=1/2 cm=0.5 cm

area of one square=(0.5)²=0.25 cm²

total area of two black squares=2×0.25=0.5 cm²

length of white rectangle=2/2=1 cm

width=2/4=1/2 cm=0.5 cm

area of one rectangle=1×0.5=0.5 cm²

area of two rectangles=2×0.5=1 cm²

total area=0.5+1=1.5 cm ²

7 0

3 years ago

I NEED HELP PLEASE !!!! REALLY REALLY NEED HELP

Nata [24]

Answer:

This is very easy

use your law of indices and find the LCM of those with minus and plus signs

6 0

3 years ago

A 40<br> B 160<br> C 80<br> D 60

IceJOKER [234]

Answer:

ithink its A miight be wrong tho hope it helps in someway ig idk

Step-by-step explanation:

6 0

4 years ago

Read 2 more answers