1-cosx是如何转化到1╱2x∧2的,我要详细详细详细

2025-04-14 11:28:06
推荐回答(1个)
回答1:

1-cosx=1-(1-2*(sinx/2)^2)=2*(sinx/2)^2,而sinx~x,所以2*(sinx/2)^2~2*(x/2)^2=1/2*x^2