Question

三角函数求起终边相等有一下四组角：⑴kπ+π/2;⑵kπ-π/2;⑶2kπ±π/2;⑷-kπ+π/2(k∈Z)其中终边相

Answer 1

⑴kπ+π/2(k∈Z)={...-5π/2,-3π/2,-π/2,π/2,3π/2,5π/2,...}

⑵kπ-π/2(k∈Z)={...-5π/2,-3π/2,-π/2,π/2,3π/2,5π/2,...}

⑶2kπ±π/2(k∈Z)={...-5π/2,-3π/2,-π/2,π/2,3π/2,5π/2,...}

⑷-kπ+π/2(k∈Z)={...-5π/2,-3π/2,-π/2,π/2,3π/2,5π/2,...}

所以其实(1)(2)(3)(4)的终边是相同的

所以选D