Just Like the pictures and the worksheet bellow, I have only changed the y's assignment position, but the result is different! So I hope someone could help me. Thanks a lot.
Solved! Go to Solution.
It is a problem that needs differentiation by parts
Your function is d/dx of a(x)*b(x) so the result should be: (d/dx a(x) ) *b(x) + a(x) * (d/dx b(x))
Unfortunately if you define f(x,y) mathcad is assuming that these parameters are independant
When later you let mathcad know that y=x^5 then it substitutes that into the result it already had,
but information is lost & you get an incorrect answer.
It is a problem that needs differentiation by parts
Your function is d/dx of a(x)*b(x) so the result should be: (d/dx a(x) ) *b(x) + a(x) * (d/dx b(x))
Unfortunately if you define f(x,y) mathcad is assuming that these parameters are independant
When later you let mathcad know that y=x^5 then it substitutes that into the result it already had,
but information is lost & you get an incorrect answer.
……but information is lost ……
OK, I should tell mathcad the informations in order. Really! I've forgotten the difference of relationship between x and y in different assignment position. Thank you very much!