Voici les articles les plus récents de notre base de données:
nouvelle recherche

		Page 380/886

	A bijection from (0,1)x(0,1) to (0,1)		2008-07-20
		Adam pose la question : I'm trying to prove that the function that takes the open square (0,1)x(0,1) to (0,1) is a bijection (and hence a continuum). If we take an element (x,y) of (0,1)x(0,1) and represent (x,y) as (0.x1 x2 x3 x4..., 0.y1 y2 y3 y4...) aka x1 represents the tenths digit of x, x2 represents the hundredths, etc. Then we can define a function f((x,y)) = 0.x1 y1 x2 y2 x3 y3... However, this is not a bijection. I hypothesize this is because you'd be unable to create the number 0.1 as x=0.1 and would have to be y=0, which contradicts the open interval (0,1) defined for y. We have been told though, if we create the same function, except that we "group" 9's with their next digit into a "block" we can create a bijection. For example, if x=0.786923 and y=0.699213, then we define x1 to x3 as normal, but x4= 92, and x5=3. For y, we define y1 as normal, but y2=992, and y3 to y4 as normal. hence f((x,y)) = 0.7 6 8 992 6 1 92 3 3. My questions are a) is my hypothesis on why the original function is not a bijection correct? b) why does the special blocking in the new function make a bijection? Victoria West lui répond.
	A square is inscribed within a square		2008-07-19
		Shirley pose la question : A square is inscribed within a square that has a side the measures 16 centimeters. The vertices of the smaller square are located at the midpoints of the sides of the larger square. What is the area of the larger square, area of a smaller square, the probability that a point chosen at random is in the shaded are? Express the answer as a simplified fraction. Penny Nom lui répond.
	Two numbers		2008-07-19
		Jerry pose la question : while driving in my car early this morning, i 'discovered' something and want to ask if there is an equation that would fit it... Here it goes..... take any two numbers (with the exception of two of the same numbers), multiply the first number by 2, add the difference of the original two numbers, and the outcome will be the same as if you added the original two numbers together... example: 3+5=8... thus, 3+3+(5-3)=8... if you chose to reverse the numbers then..... 5+3=8... thus, 5+5-(5-3)=8 i know, simple stuff.. but i just want someone to tell me what exactly this is.. is there a 'law' that describes this? Victoria West lui répond.
	equation?		2008-07-19
		Jerry pose la question : while driving in my car early this morning, i 'discovered' something and want to ask if there is an equation that would fit it... Here it goes..... take any two numbers (with the exception of two of the same numbers), multiply the first number by 2, add the difference of the original two numbers, and the outcome will be the same as if you added the original two numbers together... example: 3+5=8... thus, 3+3+(5-3)=8... if you chose to reverse the numbers then..... 5+3=8... thus, 5+5-(5-3)=8 i know, simple stuff.. but i just want someone to tell me what exactly this is.. is there a 'law' that describes this? Victoria West lui répond.
	solving four simultaneous equations		2008-07-18
		Muhammad pose la question : -2B-2C+4E=1 A+B+C+D=0 -2B-2C-2D+E=0 B+C+4D-2E=0 Janice Cotcher lui répond.
	Choosing 5 numbers out of 39 numbers		2008-07-18
		robert pose la question : Please list the way I can choose 5 numbers out of 39 numbers, without repeating them, starting at number 1. Please send me a list of all 120 combination. Harley Weston lui répond.
	The height of a triangle		2008-07-18
		Becc pose la question : I have to find the height of a triangle. The base is 3.1cm say ab One of the top sides is 4cm say ca The other side is 2cmsay cb Penny Nom lui répond.
	The cube root of a really big number		2008-07-17
		Pete pose la question : Is the only way to find a cube root of a really big number guess and check, as i read in other questions, or is there another way without a calculator? Harley Weston lui répond.
	Does the sequence 1 2 4 8 16 32 etc have a name?		2008-07-17
		Richard pose la question : Just an idle thought really. Does the simple sequence 1 2 4 8 16 32 etc have a name? Victoria West lui répond.
	Graphing Using Double Angle Identities		2008-07-16
		Hodan pose la question : the Question is: Describe how you could use your knowledge of Double angle formulas to sketch the graph of each function. Include a sketch with your description.A) F(x)=sin x cos x B)F(x)=2 cos(squared)x C) F(x)= tan(x) (divided) by 1-tan(squared) x Janice Cotcher lui répond.
	Rational numbers		2008-07-16
		hinal pose la question : list 12 rational numbers which lie between a) -1 and 0 b) -3 and -3 Penny Nom lui répond.
	The units digit of (7*3)^21		2008-07-16
		surender pose la question : what will be the unit digit of (7*3)^21?plz give me method 2 calculate such problems.thank you. Penny Nom lui répond.
	A cube inscribed in a right cone		2008-07-16
		Steven pose la question : A cube is inscribe in a right cone of radius 2 and height 5. What is the volume of the cone? Victoria West and Harley Weston lui répond.
	1, 2, 4, 8, 16, 32 ...		2008-07-15
		eve pose la question : I have to find out the fomula for: 1, 2, 4, 8, 16, 32 ... Penny Nom lui répond.
	An isosceles triangle inscribed in a circle		2008-07-15
		Anne pose la question : Here is the math problem quoted from book: "An isosceles triangle is inscribed in a circle of radius R, where R is a constant. Express the area within the circle but outside the triangle as a function of h, where h denotes the height of the triangle." Penny Nom lui répond.

		Page 380/886