asecα -2tanα =1,则a=(1+2tanα)/ secα=(1+2tanα)cosα= cosα+2sinα.bsecα +tanα =2,则b=(2- tanα)/ secα=(2- tanα) cosα=2 cosα- sinα.则a^2+b^2=( cosα+2sinα)^2+(2 cosα- sinα)^2= cosα^2+4 s...