Online Math Lessons

Can you solve this inequalitie to me?(Gilmar)
Solve in R: x4 - 10x2 + 9 0 My e-mail is : profgilmardf@gmail.com

Problem of the week 2 -(teacher)
Is it possible to find a natural number so that where is the sum of the digits of .

many methods(dduclam)
Solve the following problem by many methods ;) Let a triangle ABC while AM,AN are bisectors. Prove that AM=AN <=> isosceles triangle.

Nice_AM-GM(dduclam)
Let such that . Prove that dduclam

Could someone help me work out the first derivative(rfk)
This one has me stumped I need to find the first derivative of the following formula: 0.8 * ((100-0.05x)-1/) + 0.2 * ((100+0.2x)-1/) I don't even know where to start. If some one could show me a wor

Equation :)(dduclam) Find all positive roots of the equation: x = lg(9x + 1) (1) PS: lg = log10 (1) <=> Using Bernoulli inequality : (Equality holds for a=0 or k=0 or k=1) we have Equality holds for or ...

Find the area of a triangle with sides 3 cm, 4 cm and 5 cm(dduclam) Find the area of a triangle with sides 3 cm, 4 cm and 5 cm. This triangle is a right-angled triangle,because Area of the triangle :) ...

A problem with complex numbers(dduclam) What's the requests of problem? ...

sin cos(dduclam) Why sin^2 + cos^2 = 1 ? Because Pitago theorem show that :D () Nother value of ,using trigonometry circle ! ...

Factoring fractions to solve for X(dduclam) Is it clear now? :) ...