Question

晚上大脑死机了 如图在矩形abcd中ab=2 bc=3点e在bc上且ae=ad df垂直于ae求sin角cdf

Answer 1

DF⊥AE,所以∠ADF+∠DAF=90

ABCD为矩形,所以∠ADF+∠CDF=90

因此∠CDF=∠DAF

AD∥BC,所以∠AEB=∠DAF=∠CDF

RT△ABE中,AB=2,AE=AD=BC=3

sin∠CDF=sin∠AEB=AB/AE=2/3