1、ezplot('x^2/5^2+y^2/2^2=1')
axis equal
2(1)>> syms x
>> limit((2*x^2-2)/(x-1),1)
ans =
4
2(2)>> limit((x^2+4)/(x-7),2)
ans =
-8/5
2(3)>> limit((x^2-1)/(x^3-1),1)
ans =
2/3
2(4)>> limit((x^2+3)/(4*x^2-7),inf)
ans =
1/4 2(5)>> limit(sqrt(x^2+x)-sqrt(x^2-1),inf)
ans =
1/23(1)>> syms x y
>> z=x*log(x+y);
>> diff(z,x,2)
ans =
2/(x + y) - x/(x + y)^2
>> diff(z,y,2)
ans =
-x/(x + y)^2
>> diff(diff(z,x),y)
ans =
1/(x + y) - x/(x + y)^2 3(2)>> y=solve('x*y+x+y=1','y')
y =
-(x - 1)/(x + 1)
>> diff(y,x)
ans =
(x - 1)/(x + 1)^2 - 1/(x + 1)
3(3)>> syms x y z
>> F=x/z-log(z/y);
>> diff(F,x)/diff(F,z)
ans =
-1/(z*(x/z^2 + 1/z))
>> diff(F,y)/diff(F,z)
ans =
-1/(y*(x/z^2 + 1/z))