1.(必修4P137A13(5))sin347°cos148°+sin77°·cos58°=.
解析:sin347°cos148°+sin77°cos58°
=sin(270°+77°)cos(90°+58°)+sin77°cos58°
=(-cos77°)·(-sin58°)+sin77°cos58°
=sin58°cos77°+cos58°sin77°
=sin(58°+77°)=sin135°=.
2.(2018·全国卷Ⅱ)已知tan(α-)=,则tanα=.
解析:解法1:因为tan(α-)=,
所以=,即=,解得tanα=.
解法2:因为tan(α-)=,
所以tanα=tan[(α-)+]