如图,$\odot P$与y轴相切于点C(0,3),与x轴相交于点A(1,0),B(9,0). 直线y=kx-3恰好平分$\odot P$的面积,那么k的值是()
连接PC,PA,过点P作PD⊥AB于点D,∵$\odot P$与y轴相切于点C(0,3),∴PC⊥y轴,∴四边形PDOC是矩形,∴PD=OC=3,∵A(1,0),B(9,0),∴AB=9-1=8,$\therefore A D = \frac {1} {2} A B = \frac {1} {2} \times 8 = 4,\therefore O D = A D + O A$$= 4 + 1 = 5,\therefore$P(5,3),直线y=kx-3恰好平分$\odot P$的面积,∴点P在直线y=kx-3上,∴3=5k-3,解得$k = \frac {6} {5}$. 故选选项1-.