为什么sin²(x+π/4)-cos²(x+π/4)] =2sin²(x+π/4)-1就你之前解答的_数学解答

为什么sin²(x+π/4)-cos²(x+π/4)] =2sin²(x+π/4)-1
就你之前解答的那道三角函数题.

人气：121 ℃　时间：2020-05-23 21:52:22

解答

sin²(x+π/4)-cos²(x+π/4)] =2sin²(x+π/4)-1
因为cos²(x+π/4)] =1-sin²(x+π/4)
所以sin²(x+π/4)-cos²(x+π/4)] =2sin²(x+π/4)-1