a)
Simplificar a expressão $\phantom{X}cos\left(\dfrac{\,3\pi\,}{\,2\,}\,-\,x\right)\phantom{X}$
b)
Calcular $\phantom{X}sen^2\left(\dfrac{\,3\pi\,}{\,2\,}\,-\,x\right) + cos^2\left(\dfrac{\,3\pi\,}{\,2\,}\,-\,x\right)\phantom{X}$
c)
Calcular $\phantom{X}sen^2\,x\,+\,sen^2\left(\dfrac{\,3\pi\,}{\,2\,}\,-\,x\right)\phantom{X}$
