Question

Calcule o valor da expressao

Answer 1

$\Large\boxed{\begin{array}{l}\sf E=\dfrac{2~sen(210^\circ)+3cos(420^\circ)-3~sen(90^\circ)}{cos(180^\circ)}\\\\\sf E=\dfrac{2\cdot(-\frac{1}{2})+3\cdot(\frac{1}{2})-3\cdot1}{-1}\\\\\sf E=-(\frac{-2+3}{2}-3)\\\sf E=-(\frac{1}{2}-3)\\\\\sf E=-(\frac{1-6}{2})\\\\\sf E=-(-\frac{5}{2})\\\\\sf E=\dfrac{5}{2}\end{array}}$