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Katyanochek1 [597]
3 years ago
12

What is the sum of the first 30 odd numbers? How to calculate it without having to add all of them.

Mathematics
1 answer:
skelet666 [1.2K]3 years ago
4 0
See that odd number are in a Aritmetic progression with a1 = 1 and r = 2

30th number of sequence is given by:

a_{30}=a_1+29r\\
\\
a_{30}=1+29*2\\
\\
a_{30}=59

Now you can calculate the sun by:

S_{30}=\frac{30(1+59)}{2}=\frac{30*60}{2}=900
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Trigonometry please help! work need to be shown
solong [7]

Answer:

6.13

Step-by-step explanation:

This diagram shown is a right triangle;

USing the SOH CAH TOA idenity

Adjacent = x

Hypotenuse = 8

Angle of elevation = 40 degrees

cos theta = adj/hyp

cos 40 = x/8

x = 8cos40

x = 6.13

Hence the value of x to the nearest hundredth is 6.13

4 0
3 years ago
Whats the root and vertex for y= 2x squared -5x-604
jeyben [28]

Vertex is calculated by -b/2a

So we have -(-5)/2(2)=5/4

The root is determined through the quadratic formula:

x=(-b+sqrt(b^2-4ac))/2a

x=(-(-5)+sqrt(-5^2-4(2)(-604)))/2(2)

x=(5+sqrt(25-4832))/4

x=(5+sqrt(-4807))/4

So the root is some imaginary number

Hope this helped!

6 0
3 years ago
54) Ashley and Nicole each improved their yards by planting daylilies and ornamental grass. They
Assoli18 [71]

Answer:

Daylilies- $11, Ornamental grass- $7

Step-by-step explanation:

For this one, you want to convert this into simultaneous equations.

If we let d be cost of one daylily and o be cost of one bunch of ornamental grass, we can write the equations as 2d+3o=43 and 6d+3o=87.

From there, we can see they share a like term (3o), so we subtract one equation from the other (since they both are preceded by a +). This gives 4d=44.

Dividing both sides by 4 isolates d, leaving d=$11.

We can substitute this value into either equation to work out o (I'm using the first one as it is easier). This makes it 2×11+3o=43, or 22+3o=43.

From there, we subtract 22 from both sides, giving 3o=21, and dividing by 3 gives a final result of o=$7.

**This content involves writing and solving simultaneous equations, which you may wish to revise. I'm always happy to help!

All working out:

<em>d- cost of one daylily o- cost of one bunch of ornamental grass</em>

<em>2d+3o=43 6d+3o=87</em>

<em />

6d+3o=87

 -     -     -

2d+3o=43

=     =    =

4d      =44

÷4        ÷4

d        =11

2d+3o=43

2×11+3o=43

22+3o=43

3o=21

o=7

3 0
3 years ago
Please give me answer friend<br>​
Law Incorporation [45]

Answer:

90°

Step-by-step explanation:

right angle - 90°

.....

5 0
2 years ago
Read 2 more answers
Film travels through a projector at the rate of 170 feet per minute. How many feet of flim are in a motion picture that last 120
Vaselesa [24]

120x170=20400

hope it helps

6 0
3 years ago
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