Functions and For Loops For Polynomials
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I need to write a function that takes two inputs, a vector that is the the coefficients of a polynomial starting with the lowest degree term and a scalar to evaluate it at, I'm supposed to use a for loop to evaluate it in the function. I also cannot use '^' this built in function. Any guidance?
2 个评论
James Tursa
2020-3-31
What have you done so far? What specific problems are you having with your code?
Alex Baham
2020-3-31
采纳的回答
James Tursa
2020-3-31
1 个投票
Some guidance:
1) The sum=0 part needs to be moved outside the loop, prior to the loop starting. The way you have it the sum resets to 0 at each iteration.
2) Don't use "sum" as a variable name since that is an important existing MATLAB function name. Use something else, like "mysum" instead.
3) c is a vector of coefficients, so you should be indexing into c inside your loop. E.g., c(i)
4) The x needs to have an exponent applied to it based on the index i.
Make an attempt at these fixes and come back with any more problems you are having.
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David Hill
2020-3-31
Too bad you can't use polyval(). This might get you started.
function e=evalPoly(p,a)
x=1;
e=0;
for k=1:length(p)
e=e+p(k)*x;
x=x*a;
end
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