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Recent problems solved by 'richard1234'
richard1234 answered: 5385 problems
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Answer 333281 by richard1234(5390) on 2011-08-30 00:31:28 (Show Source):
You can put this solution on YOUR website!Method #1 is when you are multiplying two decimal numbers, count how many digits are after the decimal point for each number. For example, (36.58)(2.4), there are two digits after the decimal point in 36.58 and one digit for 2.4. Add these to get three, so after you multiply, move the decimal point three positions to the left to compensate.
Method #2 is intuition (because 36.58 times 2.4 can't equal 877.92 can it?).
There's really only one method (and maybe variations) to find where to put the decimal point, though.
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Numbers_Word_Problems/488142: How can I find all sets of three consecutive integers whose sum is between 30 and 40? 1 solutions
Answer 333267 by richard1234(5390) on 2011-08-30 00:02:18 (Show Source):
You can put this solution on YOUR website!{9,10,11},{10,11,12},{11,12,13},{12,13,14}. ({13,14,15} doesn't work)
Just eyeball it, roughly approximate by dividing by 3 and you can find all such sets.
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test/487933: How do you differentiate the properties associative,communitive, and distributive 1 solutions
Answer 333215 by richard1234(5390) on 2011-08-29 18:36:09 (Show Source):
You can put this solution on YOUR website!For any binary operation * (not necessarily addition or multiplication):
* is said to be associative if (a*b)*c = a*(b*c) for all a,b,c ∈ S (S is a set composed of all possible a,b,c)
* is said to be commutative if a*b = b*a for all a,b ∈ S
* is said to be distributive over another operation (I'll denote this operation by &) if a*(b&c) = (a*b)&(a*c) for all a,b,c ∈ S.
For example, vector addition is commutative and associative, scalar products are distributive, the dot product of vectors is commutative, and the cross product of vectors is associative over vector addition, but not commutative (in fact, it is said to be anti-commutative, similar to subtraction). These are just examples of operations other than addition or multiplication that obey these properties.
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Sequences-and-series/487949: How do you do the problem n=19 an=155 and d=8? in arithmetic sequence 1 solutions
Answer 333211 by richard1234(5390) on 2011-08-29 18:21:40 (Show Source):
You can put this solution on YOUR website!You can't "do" a certain arithmetic sequence; you have to explain what "do" means.
If a sequence is denoted a_1, a_2, ..., a_n, ... and n = 19, then a_19 denotes the 19th term of the sequence. d=8 is the common difference; i.e. each term in the sequence is 8 more than the previous one. a_n = 155 means the nth term is 155. You'll have to rephrase your problem for it to make more sense and obtain an answer.
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Average/487750: Respected Sir ,
Please help me to solve this question, I will be very grateful for your help
If a variable assumes the value 1,2,3.....5 with frequencies as 1,2,3,....5, then what is the AM ?
As the answer given is : 11/3
Please help me to simplify this !!!
1 solutions
Answer 333209 by richard1234(5390) on 2011-08-29 18:18:46 (Show Source):
You can put this solution on YOUR website!You want to find the arithmetic mean of one 1, two 2's, ..., five 5's, which is essentially
since the sum of the entries is 1^2 + ... + 5^2 and there are 1+2+...+5 entries.
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Equations/487120: which of the following could be the units digit of 57^n where n is a positive integer? Indicate all such digits:
A.) 0
B.) 1
C.) 2
D.) 3
E.) 4
F.) 5
G.) 6
H.) 7
I.) 8
J.) 9
1 solutions
Answer 333087 by richard1234(5390) on 2011-08-29 00:01:08 (Show Source):
You can put this solution on YOUR website!Same units digits as 7^n. 7^1 ≡ 7 (mod 10), 7^2 ≡ 9, 7^3 ≡ 3, 7^4 ≡ 1, 7^5 ≡ 7, and the pattern repeats. The only possible digits are 1,3,7,9.
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Linear_Algebra/487600: How do I find the x and y intercepts? Help. Do I have to guess at the numbers?
Find the x- and y-intercepts for the equation 4x – 3y = 9. Please show all of your work. Then graph the equation.
1 solutions
Answer 333085 by richard1234(5390) on 2011-08-28 23:56:32 (Show Source):
You can put this solution on YOUR website!No guessing...to find the x-intercept, set y equal to zero and solve for x. Similarly, to find the y-intercept, set x equal to zero and solve for y.
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Linear_Algebra/487277: Пlease help me with those questions!!!
1. Find all triples (x; y; z) of positive integers such that x < y < z and
(1/x)-(1/xy)-(1/xyz)=19/9
2. Show that from any five integers, one can always choose three of these integers such that their sum is divisible by 3.
Thank you very much!!!
1 solutions
Answer 333084 by richard1234(5390) on 2011-08-28 23:55:46 (Show Source):
You can put this solution on YOUR website!1. There are none. Since x < y < z, the maximum value of the LHS is about 1 (set x = 1, y,z to be large numbers). The LHS can never get larger than 1, so there are no solutions (x,y,z) of positive integers.
2. Out of any five integers, there will either exist an integer for each residue modulo 3 (in which we're done), or all five integers will occupy two different residues mod 3. If this is the case, then by a simple Pigeonhole argument, three of them have the same residue mod 3, in which we're also done (since the sum of these three is 0 mod 3).
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real-numbers/487382: It says : Name the set(s) of numbers to which each number belongs. Solve 1.93 1 solutions
Answer 333080 by richard1234(5390) on 2011-08-28 23:38:57 (Show Source):
You can put this solution on YOUR website!You didn't specify which "sets." Assuming you mean the "double-stroke" sets i.e. real, rational, integer, whole number, natural number, 1.93 is a real number and a rational number (193/100) but not an integer.
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Quadratic_Equations/487494: Explian the four steps for solving quadratic equations? Can any of these steps be eliminated? Can the order of the these steps be changed? Would you add any steps to make it easier,or to make it easier to understand? 1 solutions
Answer 333079 by richard1234(5390) on 2011-08-28 23:36:26 (Show Source):
You can put this solution on YOUR website!Either complete the square or factor. If neither of these work very well, you can use the quadratic formula. But you only need to use one method (as long as you do your arithmetic correctly). As to eliminating/adding steps, there is no need to do so, and no need to change the steps. I can't really answer those questions; you'll learn much better by practicing solving quadratic equations.
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Rectangles/487560: Lenght of a rectangle is 1 unit more than it's width.
The area of this rectangle is 30 square units.
What are the dimensions of the rectangle 1 solutions
Answer 333077 by richard1234(5390) on 2011-08-28 23:29:40 (Show Source):
You can put this solution on YOUR website!5 units by 6 units. You can do this by noting that 30 = 5*6, or by doing it the longer way by letting x(x+1) = 30 and solving via factoring.
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Graphs/487575: y = -3/4x-6
what is y if x is 8?
what is x if y is 6?
what is y if x is 0?
what is x if y is -9?
what is y if x is -4?
what is x if y is 0? 1 solutions
Answer 333076 by richard1234(5390) on 2011-08-28 23:28:45 (Show Source):
You can put this solution on YOUR website!Just plug in the variable that is known and solve for the other number. For example,
"what is y if x is 8?"
Just replace x = 8 to get y = (-3/4)(8) - 6 = -12.
Do the others the same way.
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Angles/487590: Give an exact value for sin(5pi/6 radians) don't just solve the problem explain to me how you did it! Thank you 1 solutions
Answer 333075 by richard1234(5390) on 2011-08-28 23:26:00 (Show Source):
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Geometry_Word_Problems/487566: i need to find the counterexample to this conjecture: All rectangles with a perimeter of 20ft have the same area. note: perimeter= 2(Length+Width) 1 solutions
Answer 333072 by richard1234(5390) on 2011-08-28 23:01:13 (Show Source):
You can put this solution on YOUR website!There are lots of counterexamples, so you do not need to refer to it as "the counterexample."
For example, a 4 ft * 6 ft rectangle and a 3 ft * 7 ft rectangle both have perimeter 20 ft, but their areas are different (24 ft^2 vs. 21 ft^2).
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