All categories

3 years ago

10^2+12^2+14^2+......+26^2=??

Mathematics

1 answer:

Kazeer [188]3 years ago

3 0

Answer:

3156

Step-by-step explanation:

Used formula:
(1² + 2² + 3² + ... + n²) =1/6*n(n + 1)(2n + 1)

--------

10²+12²+14²+......+26² =
(2*5)²+(2*6)² + (2*7)² + ... + (2*13)² =
4*(5²+6²+7²+...+13²) =
4*(1²+2²+...+13² - (1²+2²+3²+4²)) =
4*(1/6*13(13+1)(2*13+1) - (1+4+9+16)) =
4*(1/6*13*14*27- 30) =
4*(819 - 30) =
4*789 =
3156

You might be interested in

If 3 dice are rolled at the same time, what is the probability of all 3 dice showing even face

Bezzdna [24]

Total possible outcomes of 3 dice = 6 x 6 x 6 = 216

Total number of ways for all 3 to show even numbers:
222
224
226
242
244
246
262
264
266
.
.
etc. There 27 of them.

Probability = 27 / 216 = 1/8 = 12.5 percent .

5 0

2 years ago

MATHHHHHH I NEED HELP PLEASE!!!!!

Olin [163]

Answer:

so at (0,20) she spent all the money on (20) orange juice and 0 coffee

then at (15,0) she spent all the money on (15) coffee and 0 orange juice

Step-by-step explanation:

3 0

3 years ago

In a sample of 42 water specimens taken from a construction site, 26 contained detectable levels of lead. Construct 90% confiden

hram777 [196]

Answer:

(0.4958, 0.7422)

Step-by-step explanation:

Let p be the true proportion of water specimens that contain detectable levels of lead. The point estimate for p is $\hat{p}=26/42=0.6190$ . The estimated standard deviation is given by $\sqrt{\hat{p}(1-\hat{p})/n}=\sqrt{(0.6190)(1-0.6190)/42}=0.0749$ . Because we have a large sample, the 90% confidence interval for p is given by $0.6190\pm z_{0.05}0.0749$ where $z_{0.05}=1.6448$ is the value that satisfies that above this and under the standard normal density there is an area of 0.05. So, the confidence interval is $0.6190\pm (1.6448)(0.0749)$ , i.e., (0.4958, 0.7422).

5 0

3 years ago

CAN SOMEONE PLEASE HELP ME

vaieri [72.5K]

TSR because if u look at the lines of where their similar on the second one you match it up

6 0

2 years ago

Explain how you know whether to add or subtract when you use the distributive property to multiply?

Anettt [7]

Answer: You must see if it is a distributive property of multiplication over addition or a distributive property of multiplication over subtration.

Step-by-step explanation:

You can find two kind of expressions in this property:

- Distributive property of multiplication over addition: When you mulitply a sum by a number. For example:

$a(b+c)=ab+ac$

- Distributive property of multiplication over subtration: When you mulitply a subtration expression by a number. For example:

$a(b-c)=ab-ac$

6 0

3 years ago

Read 2 more answers