P
phuonguyenpu1995


1; chung minh rang:
c=(1+4/5)*(1+4/12)*(1+4/21).....(1+4/n*(n+4)
2: cho a
a=x-y/1+xy;
b=y-z/1+2x
chung minh rang a+b+c=a*b*c
c=(1+4/5)*(1+4/12)*(1+4/21).....(1+4/n*(n+4)
2: cho a
a=x-y/1+xy;
b=y-z/1+2x
chung minh rang a+b+c=a*b*c