高一数学题(1)化简:1-tanα·sin(α-2π)·sin(π/2+α)(2)若角α=-17/4π,试求(1)式的值(1)化简:1-tanα·sin(α-2π)·sin(π/2+α)(2)若角α=-17/4π,试求(1)式的值
问题描述:
高一数学题(1)化简:1-tanα·sin(α-2π)·sin(π/2+α)(2)若角α=-17/4π,试求(1)式的值
(1)化简:1-tanα·sin(α-2π)·sin(π/2+α)
(2)若角α=-17/4π,试求(1)式的值
答
(1)1-tanα·sin(α-2π)·sin(π/2+α)=1+tanα·sinα·cosα=1+sin²a
(2)原式=1+sin²(-17/4π)=1+sin²π/4=3/2