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Sec(2x) |
2008-11-23 |
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From Evan:
Prove that this is an identity...
sec2x = sec^2x / 2 - sec^2x
Answered by Harley Weston. |
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Tan(3x) |
2008-11-23 |
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From Evan:
Derive an expression for tan3x in terms of tanx
Answered by Harley Weston. |
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How fast is the length of his shadow changing? |
2008-11-22 |
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From Desiree:
A spotlight on the ground shines on a wall 12 m away. If a man 2 m tall walks from the spotlight toward the building at a speed of 2.3 m/s, how fast is the length of his shadow on the building decreasing when he is 4 m from the building?
Answered by Harley Weston. |
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Cubic yards of fill dirt |
2008-11-22 |
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From Donnie:
I need to know the formula to figure cubic yds of fill dirt to fill an area from 4ft. deep to 18 inches deep
this lot is on a slope and I am wanting to level 176 ft long by 4ft. deep
the sides is 115 ft. wide
the upper side is 18 inches deep.
Answered by Harley Weston. |
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Solve 3x +5= 4x-10 |
2008-11-22 |
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From Nikko:
HELP please how do I solve these type of questions? 3x +5= 4x-10 or 4x +10= 6x-8
Answered by Penny Nom. |
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Profit as a percentage |
2008-11-21 |
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From Nomar:
Cost Price is $ 556,109.64 and Selling price is $ 1,020,936.00, What is the Profit Percentage?
Answered by Harley Weston. |
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Walking around a square 3.50 acre property |
2008-11-21 |
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From Ann:
How many times do I have to walk around the perimeter of my
square 3.50 acre property to achieve 1 mile?
Answered by Penny Nom. |
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There are 30 marbles in a bag |
2008-11-21 |
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From Cori:
There are 30 marbles in a bag. Twice as many red, as blue, and 1 more green than there are red. What is the probability that when one is pulled out, it will be red?
Answered by Penny Nom. |
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Factor 9x^2 + 6x + 4 |
2008-11-21 |
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From Jonah:
how can i solve this by factoring: 9x^2 + 6x + 4
Answered by Harley Weston. |
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The distribution of sample sums |
2008-11-21 |
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From Mark:
For large samples, the sample sum (Σ x) has an approximately normal distribution.
The mean of the sample sum is n*μ and standard deviation is (σ*√n). The distribution of savings per account for savings and loan institution has a mean equal to $750 and a standard deviation equal to $25. For a sample of 50 such accounts, find the probability that the sum in the 50 accounts exceeds $38,000.
Answered by Penny Nom. |
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Evaporation of waste water |
2008-11-21 |
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From Alexandra:
Engineers know that the amount of water lost due to evaporation
is directly proportional to the surface area of the holding tanks and
that the local climate causes water to evaporate at the rate of about
gallon of water per hour for each square foot of water exposed to
the air. About how many total gallons of waste water may enter the
three tanks each day to maintain full capacity?
I know that the answer is 50x10^3 but i don't know why.
Answered by Penny Nom. |
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15 cubic yards of dirt |
2008-11-20 |
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From Phillip:
How far, in feet, will 15 cubic yards of dirt cover, if I'm laying it 12 feet wide and 4 inches deep? Please provide formula.
Answered by Penny Nom. |
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The nth term of a sequence |
2008-11-20 |
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From kim:
Find the next 2 terms of the sequence.
11n+2.5
Answered by Harley Weston. |
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Four circles in a square |
2008-11-19 |
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From Anthony:
I have a square where one side measures 10cm and within that square
There are four equal quarter circles. Each quarter circles starts in a
different corner of the square and I am trying to find area inside the
overlap on the quarter circles.
Answered by Janice Cotcher, Chris Fisher and Penny Nom. |
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The range of a set of numbers |
2008-11-19 |
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From krista:
hi, i was working on a math problem for homework and it asked me to
find the range out of these numbers:
1,15,16,16,19,25,27,28,28, can you help me?
Answered by Penny Nom. |
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