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+118725

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You can cancel out units just the same as you can cancel down numbers (in fractions)

(90 feetcubed divide by minutes ) * 45minutes/1 = 90*45 feetcubes (the minutes cancel out)

Or you can just think logically

1 cubic ft per minute for 45 minutes = 1*45cubicfeet
2 cubic ft per minute for 45 minutes = 2*45cubicfeet
...
90 cubic ft per minute for 45 minutes = 90*45cubicfeet

MelodyOct 6, 2013

+118725

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Break what down?

MelodyOct 6, 2013

+118725

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This is a really good question
I haven't seen one quite like it before.

Let the length actually purchased be x m long.
so originally the cloth is 0.9m by x m

The cloth shrinks 10% in both directions so this means that after washing the length and width are each 90% of the original.
So after shrinking the width is 90% of 0.9 = 0.9*0.9 = 0.81m
The length is 90% of x = 0.9x

Now the shrunken area is 21.87m ²
0.81 * 0.9*x = 21.87m ²
x = 21.87/0.81/0.9
x = 30 metres

MelodyOct 6, 2013

+118725

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Sorry, this is not a question.

MelodyOct 6, 2013

+118725

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This is a really good question.

a/bc = a/b*c
Multiply and divide are equally important. You just do them from left to right.
that is why it is a/b then multiply by c

MelodyOct 6, 2013

+118725

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Sorry, your question doesn't make sense

MelodyOct 6, 2013

Oct 5, 2013

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PEDMAS means to do the parentheses, equations, division, multiplication, addition and subtraction in order of how their written. I hope this helped.

GuestOct 5, 2013

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Please if you are still using this website please get off it and stop using this web site to waste my time.
p.s. the answer is 6

GuestOct 5, 2013

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[*]A fraction is the numerator divided by the denominator[list]Example#1 1/2=1 divided by 2=0.5[/list:u] Use the calculator and take the top number divided by the denominator.

It is very easy after you get the hang of it.
Trust me,sometimes,I still forget,but it'll get easier.
Just remember,use the calculator and take top/bottom(top divided by bottom).

GuestOct 5, 2013

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48/4=12

So the answer is 12 because let's say you want 2/4 of 48 instead then that would mean half or 50% of 48 which would be 24.
1/4 = 0.25 or 25% and 25% of 48 is 12.

GuestOct 5, 2013

+3146

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[input]asin(0.5)[/input]
[input]acos(0.5)[/input]

adminOct 5, 2013

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Read 2 chapters a day

GuestOct 5, 2013

+118725

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Hi scrutinizer,
It is no big deal but you missed a 2 in your final answer
(4 + 3)/2sqrt(3) = 7/ 2sqrt(3)
I also agree that 2+2/3 is an input error.

I also think that you have missed out half the solution.
I did it a bit differently
I said
7sin^2theta + 3cos^2 theta = 4
4sin^2theta + 3sin^2theta + 3cos^2 theta = 4
4sin^2theta + 3(sin^2theta + cos^2 theta) = 4
4sin^2theta + 3*1 = 4
4sin^2theta = 1
sin^2theta = 1/4
sin theta = +-1/2
theta = 30,150, 210, 330, ....degrees
cos theta = +-(root3) / 2
so sectheta+costheta = +-( 2/root3 + root3/2) = +- [7/(2root3) ] = +- ( 7root3/6 )

If you think I am wrong I would be happy to listen to your argument.

MelodyOct 5, 2013

+259

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1. 7sin^2theta + 3cos^2 theta = 4 => 7sin^2theta + 3cos^2 theta = 4(sin^2 theta + cos^2 theta) => 3sin^2 theta - cos^2 theta = 0.Arrived at homogeneous trigonometric equation, and since sin^2 theta is not equal to cos^2 theta and both are not equal to 0, we can divide the components by cos^2 theta:

3tg^2 theta = 1 =>tg theta = +-1/sqrt(3). Theta = +-arctg(1/sqrt(3)) + pi n = +- 30 degrees (or +-pi/6) + pi n

2. cosine is a symmetric function, therefore cos(-pi/6) = cos pi/6, hence sec theta + cos theta = 1/cos(pi/6) + cos (pi/6) = 2/sqrt(3) + sqrt(3)/2 = (4 + 3)/2sqrt(3) = 7/sqrt(3)

Your presentation of the task contains either methodic or typewriting error since 2 + 2/3 = 8/3 can be written as a single number, but in the context of this task this looks illogically.

scrutinizerOct 5, 2013

+118725

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I can't answer this without more information. sorry

MelodyOct 5, 2013

+118725

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firstly
They are not 'reverse' functions. They are INVERSE FUNCTIONS.

say you want inverse cos (0.5)
sometimes written as cosa(0.5) where a stands for arc which is the same as inverse
sometimes written as cos ^-1(0.5) ----- NOTE: this is totally different from [cos(0.5)] ^-1

Anyway, to put this in the web 2.0 calculator input
2nd, acos, 0.5 =

Other cals may be inv, cos ^-1, 0.5

REMEMBER
Your calculator must be set to degrees or to radians - whichever you are working in. This is easy to overlook.
The number must be between -1 and 1 inclusive. Otherwise there can be no answer and you will get an error message.

I hope this helps.

MelodyOct 5, 2013

+118725

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MelodyOct 5, 2013

+118725

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Your question does not make any sense.

MelodyOct 5, 2013

+118725

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Your question: show the sin^-1 (cosx)= x + pi/2

answer, you can't because it is not true, at least it is not true for any positive value of x because arcsin (anything) must be between -pi/2 and p/2 and this would give an answer above this range.
It may be true for x values between -pi and 0, I'll have to think about that some more.

I've only really thought this through for acute values of x (0 is less than x is less than pi/2 radians)
but
sin^-1 (cosx)= pi/2 - x (in radians)

Method 1 (0 is less than x is less than pi/2 radians)
You can show this by drawing a right angled triangle. One acute angle is x so the other one has to be pi/2-x
Let the side adjacent to x be p and the one opposite be q and the hypotenuse be h.
cos x = p/h
sine of what angle equals p/h? Sine of the angle at the other vertex equals p/h and the angle at the other vertex is pi/2-x
Try drawing the triangle - it should make it clearer.

Method 2
You can also consider it algebraically (0 is less than x is less than pi/2 radians)
arcsin[cos(x)]
= arcsin[sin(π/2 -x)]
= π/2 - x

It you want me to think about it more let me know.

MelodyOct 5, 2013

+118725

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Our guest is correct.
If you have 2 b's and you ADD 1 b you do get 2b+1b = 3b
BUT
your question is multiply NOT add

2b*b = 2*b*b= 2*b^2 = 2b^2 that is, 2bsquared

MelodyOct 5, 2013

+118725

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First expand the brackets
then plus 2 to both sides
then minus 5x off both sides
then divide both sides by the number in front of the x.
Swap sides and you will have your answer.

If this is not enough help then you can reply again with a more specific question.
I hope it helps.

MelodyOct 5, 2013

+118725

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http://en.wikipedia.org/wiki/E_(mathematical_constant)

To start with e is just a number. It has some very special properties.
I have included a web link if you want to know more.

e is approximately equal to 2.71828

It is a special number in a similar way to pi being a special number.

Pi and e are both irrational numbers

If you want to get an approximation of e on your calculator
put it in as e= or if that doesn't work try e^1=
(You may need to press the shift button first to get e)

MelodyOct 5, 2013

+6

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Thank you soooo much!!!

ARodriguez82Oct 5, 2013

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Pi equals 3.14 or 3 1/7

GuestOct 5, 2013

Oct 4, 2013

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2b*b=?
Well 2b means that there are two B's. If you add another "B" to it, then how many B's would you have? You would have three B's. So 2b*b= 3b.

GuestOct 4, 2013

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