... x->diff(f(x),x):> f1(x):> simplify(f1(x)):> a:=solve(f1(x)=0,x):> ct1:=a[1]:> ct2:=a[2]:> f(ct1):> f(ct2):> f2:=x->diff(f(x),x$2):> f2(x):> simplify(f2(x)):> ... duong_thang);> line(d1,[A,B],[x,y]):> line(d2,y=x+1,[x,y]):> detail(d1):> detail(d2):> intersection(K,d1,d2):> coordinates(K):> FindAngle(d1,d2):> distance(A,d1):> ... tentieptuyen2]);> point(C,0,0):> circle(c,[A,B,C],[x,y]):> detail(c):> radius(c):> coordinates(center(c)):> area(c):> circle(c1,[C,5],[x,y]):> detail(c1):> tangentpc(t1,C,c):>...