Reducir :E = [tex] \ frac{(sen \ alpha + cos \ alpha ) ^ {2} - (sen \ alpha - cos \ alpha ) ^ {2} }{(sen \ alpha + cos \ alpha) + (sen \ alpha - cos \ alpha ) ^ {2}} [ / tex]?

Reducir : E = [tex] \ frac{(sen \ alpha + cos \ alpha ) ^ {2} - (sen \ alpha - cos \ alpha ) ^ {2} }{(sen \ alpha + cos \ alpha) + (sen \ alpha - cos \ alpha ) ^ {2}} [ / tex].