∵0＜α＜π2，0＜β＜π2，sinα＝45，cos(α+β)＝513∴0＜α+β＜πcosα＝1−sin2α＝1−1625＝35sin(α+β)＝1−cos2(α+β)＝1−25169＝1213∴sinβ=sin[（α+β）-α]=sin（α+β）cosα-cos（α+β）sinα=1...