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Sum and difference of squares |
2011-12-31 |
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Anne pose la question :
Se x e y são números reais distintos, então:
a) (x^2 + y^2) / (x - y) = x + y
b) (x^2 + y^2) / (x - y) = x - y
c) (x^2 - y^2) / (x - y) = x + y
d) (x^2 - y^2) / (x - y) = x - y
e) Nenhuma das alternativas anteriores é verdadeira.
Harley Weston lui répond. |
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Working together |
2011-12-30 |
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Kenneth pose la question :
15 workers can finish a job in 7 days.
If I want to find the number of days 21 workers can finish the job, the calculation becomes 1/(21 workers) X 15 workers X 7 days.
If the 21 and 15 are reduced to 7 and 5, by dividing 21 and 15 by 3, the calculation becomes 1/7 X 5 X 7 days, what do these two reduced terms (7 and 5) indicate or represent?
Do they represent 5 workers and 7 workers, as in (1/7 worker) X 5 workers X 7 days = 5 days?
I thank you for your reply.
Penny Nom lui répond. |
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Limits and composition |
2011-12-30 |
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Rahul pose la question :
I want to know about limit proofs of composite functions. Like limit of log of a function equals log of limit of the function
Penny Nom lui répond. |
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Triangular numbers that are square |
2011-12-27 |
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Luke pose la question :
The “TnS” is a positive integer which is both Triangular number
and Square number. For example, 36 is a “TnS” number
since 36=1+2+3+4+5+6+7+8 (Triangular number)
and 36=6x6 (Square number).
What is the next “TnS” which is greater than 36?
Penny Nom lui répond. |
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The graph of a quadratic function |
2011-12-27 |
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Thomas pose la question :
sketch a quadratic function with zeros at -3 and 1
Penny Nom lui répond. |
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The volume of a frustum of a cone |
2011-12-24 |
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CV pose la question :
If I know the height, taper, and volume of a frustum cone,
what are its Radii?
Calculating frustum cone volume is straight forward.
v=Pi/3*h*(R*R+r*r+R*r) where;
v=volume;
h=frustum height;
R=major radius;
r=minor radius;
Pi=3.1415926;
t=taper, ('slant angle' where t=0 is a disk)
Here is the tricky part.
Knowing 'h', 't', & 'v';
Calculate one or both of 'R' & 'r'.
Specifically, what is the formula for 'R=' or 'r='?
Penny Nom lui répond. |
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Three sides of a triangle |
2011-12-24 |
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saba pose la question :
the three sides of a triangular lot have lengths 10,11and 13cm,respectively.
find the measure of its largest angle and the area of the lot?
Penny Nom lui répond. |
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The volume of a cylinder |
2011-12-22 |
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luke pose la question :
what is the volume of a cylinder that is 30 mm in diameter and 70 cm high?
can you please write the equation out in full for me to help understand it better. thanks
Penny Nom lui répond. |
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The weight of 36 inch steel pipe |
2011-12-22 |
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Keith pose la question :
What is the weight of 36 inch steel pipe 3/4 wall per foot in lbs.
Penny Nom lui répond. |
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The number of digits in a number base m |
2011-12-22 |
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Jash pose la question :
Assume there is a number system of base m.
The one property of this system is: If 2 numbers written in this system, which have 'a' and 'b' as the number of digits are multiplied, then the product of the 2 numbers will have a number of digits which is a function f(a,b).
In other words, as long as the number of digits of the 2 numbers are constant, the number of digits of their product is a constant.
Find m.
Robert Dawson lui répond. |
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A combination lock |
2011-12-21 |
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Sheila pose la question :
I have a combination lock with a total of 3 rows of single digits 1 - 9.
In order to open the lock, the numbers chosen for each row together
add to 12.I'm looking to generate a list of numbers that I can
sequentially try so that I can open the lock.
Robert Dawson lui répond. |
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Water is flowing into a cup |
2011-12-19 |
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Tim pose la question :
A cup has a radius of 2" at the bottom and 6" on the top. It is 10" high. 4 Minutes ago, water started pouring at 10 cubic " per minute. How fast was the water level rising 4 minutes ago? How fast is the water level rising now? What will the rate be when the glass is full?
Penny Nom lui répond. |
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The number of gallons in a box |
2011-12-18 |
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matt pose la question :
i need to know how many gallons a 16 inch square box will hold
Penny Nom lui répond. |
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Displacement |
2011-12-17 |
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faisal pose la question :
a helicopter takes off and travels 300 km due north then returns to its landing field. what is its displacement?
Penny Nom lui répond. |
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Rounding |
2011-12-14 |
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seth pose la question :
A decimal number rounded changed to 23.7 after it was rounded.
Give a decimal number that is less than 23.7 and another that is greater than 23.7 that each round to 23.7.
Explain to what place each number was rounded.
Penny Nom lui répond. |
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