Simplifying Algebraic Expression: A(Ls)

[nesan]

Homework Statement

Sorry, not really a homework question, just practicing for a test online.

Can someone explain how this person simplified this line.

Homework Equations

A(Ls) = (L - 2*Ls)*Ls*sin(beta) + Ls*sin(beta)*Ls*cos(beta)

becomes

A(Ls) = sin(beta)*[cos(beta) - 2]*Ls^2 + L*sin(beta)*Ls

**INFO**

Lb = L - 2*Ls
h = Ls * sin(beta)
w = Ls * cos(beta)
A = Lb * h + 2 * 1/2 * h * w

Thank you, would be great help. :)

 

[BishopPair]

He doesn't use any formulas at all. The only thing he is doing is changing the place of the brackets.

Hint: Start with eliminating the brackets in the term (L - 2*Ls)*Ls*sin(beta).