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在三角函数的和差化积与积化和差的教学中,大多数教师可能注意到这么一道计算题:求tgπ7tg2π7tg3π7的值或证明:tgπ7tg2π7tg3π7=7.近日在教学中碰到一题:求证:tgπ5·tg2π5=5;结合tgπ3=3,使我大胆猜想:对n∈N,有...
In the teaching of trigonometric function sum and difference product and product and difference, most teachers may notice such a calculation problem: find the value of tgπ7tg2π7tg3π7 or prove: tgπ7tg2π7tg3π7=7. Recently encountered a problem in teaching: verification: tgπ5 · tg2π5 = 5; combined tgπ3 = 3, so I boldly guess: for n∈N, there is ...