题　初中《地理》课本上指出 :“等高线越密 ,山越陡 ,等高线越疏 ,山就越平” ,为什么 ?解　如图所示 :设山高AD =h(定值 ) .图 1解答用图∵BD CD ,tan∠ABD =ADBD=hBD,tan∠ACD =ADCD=hCD,∴tan∠ABD tan∠ACD ,∴∠ABD ∠ACD ,∴地图上的等高线越密 ,山越陡用数学眼光看 In the junior high school “geography” textbook, it was pointed out that “the contours are denser and the mountains are steeper, the contours are more sparse, and the mountains are more flat”. Why the solution is shown in the figure: set the height of the mountain AD = h (value). 1 Solution diagram BD CD, tan ∠ ABD = ADBD = hBD, tan ∠ ACD = ADCD = hCD, ∴ tan ∠ ABD tan ∠ ACD, ∴∠ ABD ∠ ACD, ∴ The contours on the map are denser and the mountains are steeper Look with mathematics