Given x,y,z > 0 satisfy \(\dfrac{1}{x}+\dfrac{1}{y}+\dfrac{1}{z}\ge2\) . Prove that : xyz \(\le\) \(\dfrac{1}{8}\)

Find all square numbers writein by 4 digits know if we add into thousands 1 unit , add into hundreds 3 units, add into tenth 5 unit and into unit row 3 unit so that we still have a square number. 

Find the surplus in division expression :

(x + 1)(x + 3)(x + 5)(x + 7) + 2013  /   x² + 8x + 12

Solve the equation :

\(x+\dfrac{2a\left|x+a\right|}{x}=\dfrac{a^2}{x}\) 

Solve the equation :

a) (x - 3)³ - (x - 3)(x² + 3x + 9) + 6(x + 1)² = 15

b) x(x - 5)(x + 5) - (x + 2)(x² - 2x + 4) = 3

This web is too boring, the coordinator's question written by word, all the thread are by word. This is Math You Like ..... not Liter-Math You Like. So, try too fix it ...... if don't .... students in this page don't like to come here and play. 

Given triangle ABC with angle A = 90⁰ , find the value of two angle B and C know triangle ABC is the isosceles triangle

Is there anyone have another way shorter than that way ???

Prove Bunyakovsky inequality :

With 2 sets of numbers : \(\left(a_1;a_2;......;a_n\right);\left(b_1;b_2;......;b_n\right)\) so that :

\(\left(a_1^2+a_2^2+......+a_n^2\right).\left(b_1^2+b_2^2+.......+b_n^2\right)\ge\left(a_1.b_1+a_2.b_2+......+a_n.b_n\right)^2\)

Prove that :

A = 1 + 2 + 2² + 2³ + .......... + 2¹⁴ \(⋮\) 31

Prove that :  In a quadrilateral, the sum of four angles is 360

Use the sum of three angles in triangle to prove it.

You are wrong ! @Kaya Renger 

:'< , web này thành đen rồi , toàn ăn điếm không