Các câu hỏi tương tự
giup minh cau nay voi : cho tam giac ABC vuong tai A voi cac duong phan giac trong BM va CN .chung minh bat dang thuc (MC+MA)(NB+NA)/MA.NA >= 3+2√2
chung minh bat dang thuc 2(a^4+1) + (b^2 +1)^2>=2(ab+1)^2
1. cho tam giac ABC M;N lan luot la trung diem cua CA ,CB ;I la diem bat ki tren MN (I khac M;N ) C/M trong 3 tam giac ICB;ICA;IAB; co 1 tam giac ma dien tich cua no bang tong cac dien tich cua 2 tam giac con lai
2. cho tam giac ABC tren cac canh AB;AC;CA keo dai ve phia B;C;A lay B1;C1;A1 sao cho BB1=b;CC1=c; AA1=a c/m a/AC+b/ AB+c/BC>HOAC =3
cho (O) ve hai day AB va CD bat ky cat nhau tai I nam trong (O). CM tam giac AIC dong dang tam giac DIB
chung minh bat dang thuc x^4 + 5 > x^2 + 4x
cho 1 da giac bat ky co chu vi bang 12. chung minh rang co the phu kin da giac boi 1 hinh tron co ban kinh bang 3.
voi a,b,c,d la cac so duong thoa man a*b = c*d = 1. Chung minh bat dang thuc ( a+b )*( c+d ) + 4 >= 2( a+b+c+d )
Cho (O) duong kinh AB. Ve duong thang d vuong goc voi AB tai B, ve duong kinh MN bat ky khong trung voi AB. Cac tia AM va AN cat d theo thu tu tai cac diem E va F
1, Tu giac AMBN la hinh gi?
2, Chung minh Tu giac MNFE noi tiep
3, Chung minh AM . EF = AF.MN
4, Chung minh: Khi duong kinh MN quay quanh O nhung khong trung voi AB thi tam duong tron di qua 4 diem M,N,F,E luon nam tren 1 duong thang co dinh
cho tam giac ABC ,AB=5cm,AC=12cm ,BC=13cm
a) ke HE vuong goc voi BE ,HF vuong goc voi AC
chung minh rang AE.AB=.AC
b)chung minh tam giac EA F dong dang tam giac ABC