hdu2552

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 思路:

1.tan(a+b) = ( tan(a) + tan(b) ) / (1 – tan(a) * tan(b) )

2.tan( atan(x) ) = x
arctan(1/s) = arctan(1/u)+arctan(1/v)
所以得
1/s= tan( arctan(1/u)+arctan(1/v) ) 
     = (tan(arctan(1/u)) + tan(arctan(1/v)))/(1-tan(arctan(1/u))*tan(arctan(1/v))) 
     = (1/u + 1/v) / (1 - 1/(uv))
所以解得 uv = 1 + us + vs
posted @ 2016-05-17 19:38  Code-dream  阅读(103)  评论(0编辑  收藏  举报