Cho tam giac ABC co goc C=90 do ;BC= 3cm; CA= 4cm. Tia pg BK cua goc ABC ( K thuoc CA); tu K ke KE vuong goc vs AB tai E )
a).Tinh AB
b).Chung minh BC=BE
c).Tia BC cat EK tai M. So sanh KM va KE
d).Chung minh CE song song MA
cho a,b,c khac 0 thoai man ab/a+b=bc/b+c=ca/c+a
tinh gia tri bieu thuc m=ab+bc+ca/a^2+b^2+c^2
Cho a , b , c khac 0 va \(\frac{a+b}{ab}=\frac{b+c}{bc}=\frac{c+a}{ca}\) Tinh C=\(\frac{ab^2+bc^2+ca^2}{a^3+b^3+c^3}\)
Cho a,b,c la ba so khac 0 va a.b.c=1 thoả mãn: ab/a+b=bc/b+c=ca/c+a
Tính gia tri M= ab+bc+ca / a2+b2+c2
Cho 3 so a,b,c khac 0 thoa man ab/a+b=bc/b+c=ca/c+a
Tinh gia tri cua bieu thuc M=ab+bc+ca/a^2+b^2+c^2
Cho a.b,c la 3 so khac 0 thoa man : ab + a + b / a + b = bc + b + c / b + c = ca + c + a/ c + a ( voi gia thiet cac ti so deu co nghia)
Tinh gia tri bieu thuc M = ab+bc+ca+2017/ a^2 + b^2 + c^2 + 2017
Cho ab/a+b=bc/b+c=ca/c+a
Tính M=ab+bc+ca/a^2+b^2+c^2
ab/a+b=bc/b+c=ca/a+c
Tinh ab+bc+ca/a2+b2+c2
cho a,b,c thỏa mãn ab/(a+b)=bc/(b+c=ca/(c+a)
tính M=(ab+bc+ca)/(a^2+b^2+c^2)