math

问题 I need to find the largest arc created from the intersection of a circle and a rectangle. I have the center of the circle, the radius and the coordinates of the rectangle, and I need to find the angle of the intersection points with the center of the circle. I have a code that works, but it computes the solution iterating the points of the circumference, and I was wondering if there's a more elegant way to calculate the solution using trigonometry instead of "brute force". That's my code:

问题 I need to find the largest arc created from the intersection of a circle and a rectangle. I have the center of the circle, the radius and the coordinates of the rectangle, and I need to find the angle of the intersection points with the center of the circle. I have a code that works, but it computes the solution iterating the points of the circumference, and I was wondering if there's a more elegant way to calculate the solution using trigonometry instead of "brute force". That's my code:

问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 7 years ago . I have been reading an article on cryptography, and I thought to myself "How does a 32bit computer actually perform operations on a 512bit value, or even a 64 bit value?" Would anyone be able to point me in the

问题 It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center. Closed 7 years ago . I have been reading an article on cryptography, and I thought to myself "How does a 32bit computer actually perform operations on a 512bit value, or even a 64 bit value?" Would anyone be able to point me in the

问题 var a = 5.0; var b = a * 10e-12; b *= 10e+12 print(b) Why b equals 500 instead of 5? As far as I know 10^(-12) equals to 1/(10^12), how can i rewrite the code? 回答1: Because math. 10e1 is 100 and 10e-1 is 1 . 10e1 * 10e-1 is 100 . 10e2 * 10e-2 is 100 . 10e3 * 10e-3 is 100 . You can very easily extend this to figure out that 10eN * 10e-N is always going to be 100 . If you want actual scientific notation, as in 1 * 10 ^ 2 , you want 1e12 and 1e-12 . 回答2: 10 -12 × 10 12 = 1 But what you wrote

问题 I am trying to solve a problem in computational algebra using python. Basically given two sets, say A={a,b} and B={e} , I need to compute the element by element tensor products and get a final set say C={a\tensor{e},b\tensor{e}} containing these products of elements. I can do an element by element multiplication using arrays with numbers but I can't do an element by element tensor multiplication of letters instead of numbers. 回答1: Not sure if I understood correctly, this below code multiplies

问题 I am working on stochastic differential equations for the first time. I am looking to simulate and solve a stochastic differential equations in two dimensions. The model is as follows: dp=F(t,p)dt+G(t,p)dW(t) where: p is a 2-by-1 vector: p=(theta(t); phi(t)) F is a column vector: F=(sin(theta)+Psi* cos(phi); Psi* cot(theta)*sin(phi)) G is a 2-by-2 matrix: G=(D 0;0 D/sin(theta)) Psi is a parameter and D is the diffusion constant I wrote code as follows: function MDL=gyro_2dim(Psi,D) % want to

问题 This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center. Closed 6 years ago . I am working on a shopping cart function for a website and have stumbled across this error: Fatal error: Unsupported operand types in ... on line 77 I

问题 First of all thanks for your time reading my question :-) I have an original image (w': 2124, h': 3204) and the same image scaled (w: 512, h: 768). The ratio for width is 4.14 (rw) and the ratio for height is 4.17 (rh). I'm trying to know the coordinates (x', y') in the original image when I receive the coordinates in the scaled image (x, y). I'm using the formula: x' = x * rw and y' = y * rh . But when I'm painting a line, or a rectangle always appears a shift that is incremented when x or y

问题 Let's say I have a short vector x = [a,b,c,d,e]; What would be the best way to compute all the difference between members of the vector as: y = [e-d e-c e-b e-a d-e d-c d-b d-a c-e c-d c-b c-a b-e b-d b-c b-a a-e a-d a-c a-b]; Thanks in advance 回答1: To give that exact matrix, try: x = [1;2;3;4;5]; %# note this is a column vector (matrix of rows in general) D = squareform( pdist(x,@(p,q)q-p) ); U = triu(D); L = tril(D); y = flipud(fliplr( L(:,1:end-1) - U(:,2:end) )) result in this case: y = 1