a) [tex3](a-b)^{2}[/tex3] [tex3]\cdot [/tex3] [tex3]\frac{\cos \alpha }{2}[/tex3]
b) [tex3](a-b)^{2}[/tex3] [tex3]\cdot [/tex3] [tex3]\frac{\sen \alpha }{2}[/tex3]
c)[tex3](a-b)^{2}[/tex3] [tex3]\cdot \sen \left(\frac{\alpha }{2}\right)[/tex3]
d) [tex3](a-b)^{2}[/tex3] [tex3]\cdot [/tex3] [tex3]\sen \alpha [/tex3]
e) ab [tex3]\cdot [/tex3] [tex3]\frac{\cos \alpha }{2}[/tex3] .
Resposta
B