I have to find the tangent lines to the circle x^2+y^2+6*x-8*y+25 = 1/16 which pass at the O(0;0) 

So i make a general line y=m * x

Ho can i put m*x instead of y in the circle and calculate the delta of the equation that i get?

I have to plot 10 squares each one inscribed into each other. After the first one, which is a square with a side of 10m, each following square has got each edges wich are distant from the previous edges (side of the previous square)/4 metres, on the

sides of the previous square

How can i draw it?

I have to generate a random list of 30 elements and i have two variables: s, which is a counter for all the list which have got at least a repetition and variable n, for each list who has not repeated values, as in the code below.

I don't understand why, when i sum s and m i get a value which is not 100, why?

for i by 1 to 100 do
		list:=RandomTools[Generate](list(integer(range = 1 .. 365), 30));
		if numelems(FindRepetitions(lista)) >= 1 then
			s:=s+1;
		
		else		n:=n+1;
				
				end if;
				end do;

I have to find which column of a matrix contains repeated elements, i have done it in this but i'm afraid that the nested loops don't run correctly:

for j by 1 to 10 do 
for i by 1 to 30 do 
	h:=Dati[i,j];
	for x by 1 to 30 do
		
		if Dati[x,j] = h then
			if x <> i then
				return j;
				end if;
				end if;
				end do;
				 end do;
				  end do;

How can i convert each column of a matrix(30X10) in a list?