Melody

Thanks Dragonlance and 4338 :)

Does comma [,] increase the number? I.e. is 10,000 10000 or is it 10

So in other words,  

10,000 may mean 10 000 (ten thousand)  or it may mean 10.000 (ten)

It depends what country you are in. (and it may reflect the age of the writer)

I assume that you have seen these on calculators.

They have to do with finding angles and side lengths of right angled triangles.

Well anyway that is what you use them for when you first learn them.

It is a very big mathematical subject called trigonometry. :

how to solve x*y=300 2x+2y=70

X+y=35

X=35-y

y(35-y)=300

-y^2+35y=300

Y^2-35y+300=0

(Y-15)(y-20)=0

Y=15,    x=20

or

y=20,    x=15

If you mean your statistics question I dont understand it either. Sorry :/

what is the value of x if cos x = sin(20+x)

You have sine and cosine

The co stands for complementary

Complementary angles add to 90 degrees.

So

20+x=90-x

2x=70

X=35

Our guests answer is good but I will just show you how to do it formally,

Let the first number be x

and the next even number will be x+2

x(x+2)=168

x^2+2x-168=0

I want two numbers that multiply to -168 and add to 2

Since they multiply to a negative,  one has to be neg and one pos

Since they add to a pos the 'biggest' one is positive

factor(168) = (2^3*3)*7

168=2*2*2*3*7 = (2*2*3)*(2*7) = 12*14

so the numbers are  14 and -12

(x+14)(x-12)=0

x=-14 or 12

so the integers are  -14 and -12 

or

12 and 14

just like our guest already said.  :)

A rectangular table is three times as long as it is wide.If thearea is 108ft^2, find the legth and the width of the table.

L=3w

L * w = 108

3w * w = 108

w*w = 108/3

w*w=36

w=sqrt(36)=6

L=3*6 = 18

width is 6 feet and length is 18 feet

check

6*18=108ft^2      

Limited
Countless number 630/429 between two numbers relative to two digits after the comma

The translation is not very clear

but

630 / 429 = 1.4685....

this is between

1.46  and  1.47

To two decimal places is is equal to 1.47

I hope that helps.   

الترجمة ليست واضحة جدا
لكن
630/429 = 1.4685 ....
هذا هو بين
1.46 و 1.47
إلى منزلتين عشريتين وتساوي 1.47
وآمل أن يساعد.
 

(1+0.021/12)^1-1

Any number to the power of 1 stays the same so this is

1 + 0.021/12.  - 1

=  0 021/12

= 21/12000

=0.00175

Why would your calc say 2.1?

Thanks anonymous4338.  I read it wrong.  I will edit my answer.  :/    

ok I fixed mine, it is ACB just like anonymous4338 and buubleman already found. 

Great work you two