ta có : \(\left(\sqrt{7}\right)^2=7\)vì 7 là số nguyên tố nên căn 7 sẽ là số vô tỉ ( mk nghĩ vậy) ^^
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6 tháng 2 2022 lúc 19:25
Given a triangle ABC. D is a point on AB and E is a point on AC so that DE//BC and frac{BC}{DE}sqrt{2}, F is a point on BC and G is a point on AB so that FG//AC and frac{AC}{FG}sqrt{2}, H is a point on BC and I is a point on AC so that HI//AB and frac{AB}{HI}sqrt{2}. FG meets HI at X, DE meets HI at Y and DE meets FG at Z.i) Prove that DYZEii) Find the exactly value of the ratio frac{YZ}{BC}
Đọc tiếp
Given a triangle ABC. D is a point on AB and E is a point on AC so that DE//BC and \(\frac{BC}{DE}=\sqrt{2}\), F is a point on BC and G is a point on AB so that FG//AC and \(\frac{AC}{FG}=\sqrt{2}\), H is a point on BC and I is a point on AC so that HI//AB and \(\frac{AB}{HI}=\sqrt{2}\). FG meets HI at X, DE meets HI at Y and DE meets FG at Z.
i) Prove that \(DY=ZE\)
ii) Find the exactly value of the ratio \(\frac{YZ}{BC}\)
23 tháng 3 2022 lúc 22:00
Circle O has diameters AB and CD perpendicular to each other. AM is any chord intersecting CB at N.I is the center of the circle inscribed in triangle AMB. Prove that M, I, D are collinear points
9 tháng 6 2018 lúc 9:21
Let x = y = z, Prove that:
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(By: Wrecking Ball)
Hi vọng sẽ không bị trùng
20 tháng 4 2021 lúc 23:12
Let x, y, z be positive real numbers such that xy + yz + zx + xyz = 4 . Prove that :
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lamf tis baats ddawngr thwcs :))
Let a,b,c be positive real numbers. Prove that : \(\frac{1}{a\left(b+1\right)}+\frac{1}{b\left(c+1\right)}+\frac{1}{c\left(a+1\right)}\ge\frac{3}{\sqrt[3]{abc}\left(1+\sqrt[3]{abc}\right)}\)
12 tháng 1 2022 lúc 19:18
Given an acute triangle ABC, its median AM and its heights BH and CK. The line passes through A and perpendiculars with AM cuts BH and CK at D and E, respectively. Prove that \(\Delta DEM\)is an isosceles triangle.
\(\dfrac{\sqrt{7}+\sqrt{5}}{\sqrt{7}-\sqrt{5}}+\dfrac{\sqrt{7}-\sqrt{5}}{\sqrt{7}+\sqrt{5}}\)
\(\dfrac{\sqrt{7}+\sqrt{5}}{\sqrt{7}-\sqrt{5}}+\dfrac{\sqrt{7}-\sqrt{5}}{\sqrt{7}+\sqrt{5}}\) bằng
Tính
a) \(\sqrt{7-4\sqrt{3}}-\sqrt{7+4\sqrt{3}}\)
b) \(\sqrt{4+\sqrt{7}} -\sqrt{4-\sqrt{7}}\)
c) \(\sqrt{4-\sqrt{10-2\sqrt{5}}}-\sqrt{4+\sqrt{10-2\sqrt{5}}}\)