Trong 1 tam giac ,chung minh 3 khang dinh sau :
a) Goc doi dien voi canh lon hon la goc lon hon
b) Canh doi dien voi goc lon hon la canh lon hon
c) Neu 1 duong thang di qua trung diem cua 1 canh ,song song voi canh thu hai thi di qua trung diem cua canh con lai
GIUP MINH NHA CAC BAN MINH GAP LAM
c/m voi 3 so thuc tuy y ta co
a2 cong b2 cong 1 lon hon hoac bang ab cong a cong b
Trong 1 tam giac ,chung minh 3 khang dinh sau
a) Goc doi dien voi canh lon hon la goc lon hon
b) Canh doi dien voi goc lon hon la canh lon hon
c) Neu 1 duong thang di qua trung diem cua 1 canh ,song song voi canh thu 2 thi di qua trung diem cua canh con lai
GIUP MINH NHA CAC BAN OI
Tim GTNN
x+1/x lon hon hoac bang 2
(mn giúp mih voi chi con 30p)
cmr : a^2/b^2 +b^2/c^2+c^2/a^2 luon luon lon hon hoac bang c/b+ b/a+ a/c voi a,b,c lon hon 0
chung minh P=x^4 - 2x^3 + 2x^2 - 2x + 1 lon hon hoac = 0 voi moi gia tri cua x
Cho a1 , a2, a3 ... , a9 duoc xd boi cong thuc:
ak= 3k^2+3k+1/(k^2+k)^3 voi moi k lon hon hoac bang 1
tong 1+a1+a2+....+a9 co gia tri
cho a,b,c lon hon hoac bang 1.Tim gtln cua P = (a+1)(b+1)(c+1)/abc+1
chung minh rang trong mot hinh thang khong can thi duong cheo doi dien voi goc o day lon hon thi lon hon duong cheo doi dien voi goc day nho hon