How to use three- line loop with disp to find derivative

I want to find the first five derivatives of f(x)=x((2x+1)^1/2), Using the three-line for loop wih disp.

Answer 1

[Andrei Bobrov]

syms x real
f = x.*(2*x+1).^(1/2)
df = arrayfun(@(i1)diff(f,x,i1),1:5,'un',0);
out = cat(1,df{:})

:)

out = sym('out',[5, 1]);
x = sym('x');
for i1 = 1:5
   out(i1) = diff(x.*(2*x+1).^(1/2),x,i1);
end

[Dhurgham Kadhim]

The answer is correct, but it is not the for-end loop's method.

Answer 2

[Jan]

You cannot find the derivative using a FOR-loop. As far as I can see, you only can use forward, backward or central differences to calculate an approximation of the derivative.

It is not clear what a "three-line for loop" is any what "with disp" exactly mean. It seems like you got a strange homework assignment.

Answer 3

[G A]

syms y x

y=x*(2*x+1)^(1/2);

f{1}=diff(y,x);

for n=2:5, f{n}=diff(f{n-1},x);end

f{:} %is this what you mean disp?

[Dhurgham Kadhim]

disp means display the answer. I evulated your steps but did not give me the derivative. Thanks

[G A]

strange... you can just copy this code to the matlab window and press 'enter'. Do not forget f{:}