## #math - Mon 19 Mar 2007 between 00:01 and 00:15

### NY Lost Funds

 ved % Expand[(5xy-2z)^4] mbot ved: 625*xy^4 - 1000*xy^3*z + 600*xy^2*z^2 - 160*xy*z^3 + 16*z^4 bsmntbombdood % Expand[(a+b)^23] mbot bsmntbombdood: a^23 + 23*a^22*b + 253*a^21*b^2 + 1771*a^20*b^3 + 8855*a^19*b^4 + 33649*a^18*b^5 + 100947*a^17*b^6 + 245157*a^16*b^7 + 490314*a^15*b^8 + 817190*a^14*b^9 + 1144066*a^13*b^10 + 1352078*a^12*b^11 + 1352078*a^11*b^12 + 1144066*a^10*b^13 + 817190*a^9*b^14 + 490314*a^8*b^15 + 245157*a^7*b^16 + 100947*a^6*b^17 + 33649*a^5*b^18 + 8855*a^4*b^19 + 1771*a^3*b^20 + 253*a^2*b^21 + 23*a*b^22 +b^23 bsmntbombdood the little triangle thing. sdfsdfdsfdf is there any way to make partial derivatives in mathematica look prettier instead of the weird exponential notation?like df[x,y]/dx instead of f^(1,0)[x,y] ved I don't believe it, but it looks as if mbot is incorrect.:(% Expand[(5xy-2z)^4] mbot ved: 625*xy^4 - 1000*xy^3*z + 600*xy^2*z^2 - 160*xy*z^3 + 16*z^4 ved The first term; it should be 625x^4y^4 sdfsdfdsfdf i think you forgot a space between x and y ved Ah, that's my bad then. sdfsdfdsfdf it's thinking they're one variable ved Got it.mbot remains unquestioned. sdfsdfdsfdf :) ved % Expand[(5*x*y-2*z)^4] mbot ved: 625*x^4*y^4 - 1000*x^3*y^3*z + 600*x^2*y^2*z^2 - 160*x*y*z^3 + 16*z^4 Domber guys, i try to define a two-dimension array ... as a matrix, so can i write:$A_{i,j}$ := $\sum_{j=0}^n \sum_{i=0}^1$ me22 ved: naw, it's wrong at times:% Limit[ Abs[x]/x, x->0 ] mbot me22: 1 Domber this is a two-dimensional array, isnt it? ved me22: Though I still think mbot is a most excellent piece of work. Olathe Domber: I don't get it. What are you summing ? me22 absolutely Jin_ how can u parametrize the line enclosed by y = 3 - x^2 and y = x^4 + 1? Olathe % Sum[, {i, 0, 1}] mbot Olathe:Syntax::com: Warning: comma encountered with no adjacent expression; the expression will be treated as Null.2*Null me22 that encloses a domain, not a line, jin_ ... Domber Olathe: i try to express a two-dimensions array in a mathematical way Jin_ me22, yep,