Help needed please, thank you!

PLEASE HELP ME!

algol13

Step-by-step explanation:

$1.\sum_{i=1}^{5}3i$

The simplest method is "brute force". Calculate each term and add them up.

∑ = 3(1) + 3(2) + 3(3) + 3(4) + 3(5)

∑ = 3 + 6 + 9 + 12 + 15

∑ = 45

$2.\sum_{k=1}^{4}(2k)^{2}$

∑ = (2×1)² + (2×2)² + (2×3)² + (2×4)²

∑ = 4 + 16 + 36 + 64

∑ = 120

$3.\sum_{k=3}^{6}(2k-10)$

∑ = (2×3−10) + (2×4−10) + (2×5−10) + (2×6−10)

∑ = -4 + -2 + 0 + 2

∑ = -4

4. 1 + 1/4 + 1/16 + 1/64 + 1/256

This is a geometric sequence where the first term is 1 and the common ratio is 1/4. The nth term is:

a = 1 (1/4)ⁿ⁻¹

So the series is:

$\sum_{j=1}^{7}(\frac{1}{4})^{j-1}$

5. -5 + -1 + 3 + 7 + 11

This is an arithmetic sequence where the first term is -5 and the common difference is 4. The nth term is:

a = -5 + 4(n−1)

a = -5 + 4n − 4

a = 4n − 9

So the series is:

$\sum_{j=1}^{5}(4j-9)$

5 0

3 years ago

A moving sidewalk takes zoo visitors up a hill. The

irina [24]

Answer:

x = 185.458 ft

Step-by-step explanation:

When we draw a picture, we are able to see that we need to use sin∅ to solve this problem:

sin15° = 48/x

xsin15° = 48

x = 48/sin14°

7 0

3 years ago

What is the length of (AB)?

earnstyle [38]

AB = 4 units
BC = 8 units
perimeter = 2(l+b) = 2(8+4) = 2(12) = 24 units

hope it helps...!!!

3 0

2 years ago

Read 2 more answers

An appliance manufacturer claims to have developed a compact microwave oven that consumes a mean of no more than 250 W. From pre

melamori03 [73]

Answer:

We conclude that a compact microwave oven consumes a mean of more than 250 W.

Step-by-step explanation:

We are given that an appliance manufacturer claims to have developed a compact microwave oven that consumes a mean of no more than 250 W with a population standard deviation of 15 W.

They take a sample of 20 microwave ovens and find that they consume a mean of 257.3 W.

Let $\mu$ = mean power consumption for microwave ovens.

So, Null Hypothesis, $H_0$ : $\mu$ $\leq$ 250 W {means that a compact microwave oven consumes a mean of no more than 250 W}

Alternate Hypothesis, $H_A$ : $\mu$ > 250 W {means that a compact microwave oven consumes a mean of more than 250 W}

The test statistics that would be used here One-sample z test statistics as we know about the population standard deviation;

T.S. = $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, $\bar X$ = sample mean power consumption for ovens = 257.3 W

σ = population standard deviation = 15 W

n = sample of microwave ovens = 20

So, the test statistics = $\frac{257.3-250}{\frac{15}{\sqrt{20} } }$

= 2.176

The value of z test statistics is 2.176.

Now, at 0.05 significance level the z table gives critical value of 1.645 for right-tailed test.

Since our test statistic is more than the critical value of t as 2.176 > 1.645, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which we reject our null hypothesis.

Therefore, we conclude that a compact microwave oven consumes a mean of more than 250 W.

7 0

2 years ago

The last time brea played softball she hit the ball 35 percent of the times she was at bat based on this information how many ti

WITCHER [35]

Answer:

The answer to your question is 7 times

Step-by-step explanation:

Data

Percent of accuracy = 35%

Times she is at bat = 20

Times she hit the ball = ?

Process

1.- Use proportions to solve this problem

20 times will be the 100% because is the total number of times she is at bat.

20 times ------------------ 100%

x ------------------ 35%

x = (35 x 20) / 100

x = 700 / 100

x = 7

2.- Conclusion

From 20 times she is at bat, she will hit the ball 7 times.

4 0

3 years ago