:2019春九年级数学下册第一章直角三角形的边角关系提升训练（北师大版）

: 直角三角形的边角关系
章末小结与提升
 
直角三角形的边角关系{■("锐角三角函数" {■("定义" {■(sinA=(∠A"的对边" )/"斜边" =a/c@cosA=(∠A"的邻边" )/"斜边" =b/c@tanA=(∠A"的对边" )/(∠A"的邻边" )=a/b)┤@"锐角三角函数间关系" {■(sinA=cosB"," tanA"•" tanB=1@sin^2 A+cos^2 A=1"," tanA=sinA/cosA)┤@"特殊角的三角函数值" {■(sin30"°" =▁(" "  1/2 " " ) "," sin45"°" =√2/2 "," sin60"°" =√3/2@cos30"°" =√3/2 "," cos45"°" =√2/2 "," cos60"°" =1/2@tan30"°" =√3/3 "," tan▁(" " 45"° " )=1"," tan60"°" =√3)┤@ )┤@"解直角三角形" {■("解直角三角形" {■("定义:由直角三角形中已知的元素,求出所有未知元素的过程" @"常用关系式" {■("三边之间的关系" a^2+b^2=c^2@"两锐角间的关系" &