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Sum and difference of squares |
2011-12-31 |
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From Anne:
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.
Answered by Harley Weston. |
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Working together |
2011-12-30 |
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From Kenneth:
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.
Answered by Penny Nom. |
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Limits and composition |
2011-12-30 |
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From Rahul:
I want to know about limit proofs of composite functions. Like limit of log of a function equals log of limit of the function
Answered by Penny Nom. |
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Triangular numbers that are square |
2011-12-27 |
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From Luke:
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?
Answered by Penny Nom. |
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The graph of a quadratic function |
2011-12-27 |
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From Thomas:
sketch a quadratic function with zeros at -3 and 1
Answered by Penny Nom. |
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The volume of a frustum of a cone |
2011-12-24 |
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From CV:
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='?
Answered by Penny Nom. |
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Three sides of a triangle |
2011-12-24 |
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From saba:
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?
Answered by Penny Nom. |
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The volume of a cylinder |
2011-12-22 |
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From luke:
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
Answered by Penny Nom. |
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The weight of 36 inch steel pipe |
2011-12-22 |
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From Keith:
What is the weight of 36 inch steel pipe 3/4 wall per foot in lbs.
Answered by Penny Nom. |
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The number of digits in a number base m |
2011-12-22 |
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From Jash:
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.
Answered by Robert Dawson. |
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A combination lock |
2011-12-21 |
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From Sheila:
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.
Answered by Robert Dawson. |
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Water is flowing into a cup |
2011-12-19 |
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From Tim:
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?
Answered by Penny Nom. |
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The number of gallons in a box |
2011-12-18 |
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From matt:
i need to know how many gallons a 16 inch square box will hold
Answered by Penny Nom. |
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Displacement |
2011-12-17 |
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From faisal:
a helicopter takes off and travels 300 km due north then returns to its landing field. what is its displacement?
Answered by Penny Nom. |
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Rounding |
2011-12-14 |
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From seth:
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.
Answered by Penny Nom. |
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