Recent content by blob84

Hello the proof of the Spiser's book (introduction to theory of computation): PROOF We let R be a TM that decides REGULARTM and construct TM S to decide ATM. Then S works in the following manner. S = "On input (M, w), where M is a TM and w is a string: 1...

Hello, using octave when I evaluate this expression (1+1/x)*x-x, with x = 10^(15) i get as result 1.125, I didn't undesrtood why, I know that octave show 15 digits in format long so when i evaluate (1+1/x)*x i get 1e15, the last digit is not visible and it is 1, so when i do substraction i get...

R_1 and R_2 are not disjoint.

Hi, if in an urn there are 3 red balls and 2 white balls and we draw 2 balls from the urn without replacement. If we assume that at each ball in the urn is equally likely to be chosen, what is the probability that both balls are red? I know the solution is \frac{\binom{3}{2}}{\binom{5}{2}}...

yes only 2 head, oh my god! Thanks.

k is the number of the head in A, int the example k = 2, any vector of A has at least two head. you flip a coin n-times, so if n = 3 you flip the coin 3 times, the problem is to count the number of vectors in A. PS. h is head.

If we flip a coin n-times, what is the probability of the event $$A= \left \{there \space are \space k \space head \right \}$$. I should find the number of elements of A, the book says that is $$\binom{n}{k}$$ but for $$n=3$$ and $$k=2$$, all the possible outcomes are: $$A= \left \{(h, h,h)...

It is \binom{6}{2}*\binom{4}{2}*7^2 by the general form of the product rule, where there are for any pairs of digits 3 cases, if I'm not wrong, thank you. I suppose to get this weird formula it calculate permutation with repetition and it brokes the problem in two sets.

How many numbers of 6 digits which have exatctly the digit 1 (2 times), digit 2 (2 times), without zero, are there? The book post this solution: \frac{6!}{2!2!}*\binom{7}{2} + \frac{6!}{2!2!2!}*7= 4410, but I'm trying to find an explanation for this result.

AHC and HBC are two triangles that we get if we draw a line from the bottom of R to the floor and by the cosine theorem we get y_i=AB-BH, there isn't the total height.

Homework Statement http://img94.imageshack.us/img94/3053/ph1d.png How does he get y_i=R-Rcos(theta)? The Attempt at a Solution if we get two triangles HBC and AHC, Rcos(theta)=AH, AB=AH+BH and AB-BH=AH=y_i.

the magnitude of the vector is: sqrt((a_c)^2+(a_t)^2)=sqrt((1.25^2+0.4^2))=1.31m/s^2 and the angle should be arctan(a_t/a_c)=arctan(0.4/1.25)=17.7°.

Homework Statement A point on a rotating turntable 20.0 cm from the center accelerates from rest to a final speed of 0.700m/s in 1.75s. (a) At t = 1.25s, find the magnitude and direction of the radial acceleration, (b) the tangential acceleration, and(c) the total acceleration of the point...

no, but i have no idea how to solve.

Homework Statement In an assembly operation illustrated in Figure P1.49, a ro-bot moves an object first straight upward and then also tothe east, around an arc forming one quarter of a circle of radius 4.80cm that lies in an east–west vertical plane. Therobot then moves the object upward and to...