+Tính được ∠B= 60o 

+Tính AC = ABtanB

=  3.tan60o = 3√3 (cm)

+Tính được BC   = 6cm 

Ủa mua Vip là giáo viên trả lời hả? :>

\(P=\left(\frac{x+\sqrt{x}-4}{x+\sqrt{x}-3\sqrt{x}-3}+\frac{\sqrt{x}-1}{3-\sqrt{x}}\right):\left(\frac{\sqrt{x}-2-\sqrt{x}+3}{\sqrt{x}-2}\right)\)

\(P=\left(\frac{x+\sqrt{x}-4}{\sqrt{x}\left(\sqrt{x}+1\right)-3\left(\sqrt{x}+1\right)}+\frac{\sqrt{x}-1}{3-\sqrt{x}}\right):\frac{1}{\sqrt{x}-2}\)

\(P=\left(\frac{x+\sqrt{x}-4}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-3\right)}-\frac{\sqrt{x}-1}{\sqrt{x}-3}\right).\left(\sqrt{x}-2\right)\)

\(P=\left(\frac{x+\sqrt{x}-4-\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-3\right)}\right).\left(\sqrt{x}-2\right)\)

\(P=\frac{x+\sqrt{x}-4-x+\sqrt{x}-\sqrt{x}+1}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-3\right)}.\left(\sqrt{x}-2\right)\)

\(P=\frac{\sqrt{x}-3}{\left(\sqrt{x}+1\right)\left(\sqrt{x}-3\right)}.\left(\sqrt{x}-2\right)\)

\(P=\frac{1}{\sqrt{x}+1}.\left(\sqrt{x}-2\right)\)

\(P=\frac{\sqrt{x}-2}{\sqrt{x}+1}\)

Mình không biết ? Đọc trong THÔNG TIN ghi là GV trả lời cho VIP's member mà bạn.

Thay vì tìm Max của a, ta tìm min của 1/a

1/a =

\(\frac{x^2+2}{x+2}\)= x - 2 + \(\frac{6}{x+2}\)

= x+2 + \(\frac{6}{x+2}\) - 4

1/a > 0 => x+2 > 0

=> 1/a >= -4 + 2\(\sqrt{6}\)

Dấu = xảy ra khi x+2 = \(\frac{6}{x+2}\)

=> x₁ = \(\frac{-4-\sqrt{24}}{2}\) (Loại vì x+2 < 0)

hoặc x₂ = \(\frac{-4+\sqrt{24}}{2}\)

Vậy 1/a đạt max tại x₂. Thay x₂ vào biểu thức a ta được giá trị max của a.

Max(a) = ...

lịt mới học lớp 8

999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999 cục mụn

999999999999999999999999999999999999999999999999999999999999999999999 cục mụn

=100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

khổ thân cái máy tính

246913578 nha

tk cái

246913578