삼각함수 공식 이해

출처 : <A href="http://blog.naver.com/PostView.nhn?blogId=jsjhahi&logNo=200714261">http://blog.naver.com/PostView.nhn?blogId=jsjhahi&logNo=200714261</A>   삼각 함수의 정의   - 직각 삼각형의 θ에 대해서 각각 변의 길이를 비로 나타낸 함수이다. - θ란? 두 변사이의 기울기를 의미한다. - 따라서, 기울기( 각도 )는 변하지 않은체 길이가 변해도 길이의 비는 성립된다.       <DIV style="TEXT-ALIGN: justify; BACKGROUND-COLOR: rgb(255,255,255); FONT-FAMILY: 돋움"><IMG style="BORDER-BOTTOM: rgb(0,0,0); BORDER-LEFT: rgb(0,0,0); BORDER-TOP: rgb(0,0,0); CURSOR: pointer; BORDER-RIGHT: rgb(0,0,0)" id=20130715_152/jsjhahi_1373886350108L5Nng_JPEG/11.JPG class=_photoImage alt="" src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fpostfiles9.naver.net%2F20130715_152%2Fjsjhahi_1373886350108L5Nng_JPEG%2F11.JPG%3Ftype%3Dw2" width=378 height=411></DIV>   COS θ =  밑변 / 빗변; SIN  θ =  높이 / 빛변; TAN θ =  높이 / 밑변;              이라는 길이의 비가 성립된다. <DIV class=autosourcing-stub-extra>   출처 : <A href="http://blog.naver.com/PostView.nhn?blogId=ohrak22&logNo=30112519627">http://blog.naver.com/PostView.nhn?blogId=ohrak22&logNo=30112519627</A> radian값과 각에 대한 변환 값 #define RadToDeg 57.29577951f #define DegToRad 0.017453293f 라디안 단위의 각에 RadToDeg를 곱하면 도 단위의 각이 됨 도 단위의 각에 DegToRad을 곱하면 라디안 단위의 각이 됨   삼각함수 삼각함수는 회전, 벡터, 물리학, 진동 현상등에 사용됩니다. <IMG style="CURSOR: pointer" id=20110706_140/ohrak22_1309951824993boxbS_JPEG/%BB%EF%B0%A2%C7%D4%BC%F6.jpg class=_photoImage alt="" src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fpostfiles13.naver.net%2F20110706_140%2Fohrak22_1309951824993boxbS_JPEG%2F%25BB%25EF%25B0%25A2%25C7%25D4%25BC%25F6.jpg%3Ftype%3Dw2" width=480 height=180>   사인, 코사인, 탄젠트는 직각 삼각형의 세 변 중 두 변의 길이로 만드는 분수, 또는 비율이다.   예제 1 - 다음 정삼각형의 사인, 코사인, 탄젠트 정의하기 <IMG style="CURSOR: pointer" id=20110706_219/ohrak22_1309955630792wbPM6_JPEG/%BB%EF%B0%A2%C7%D4%BC%F63.jpg class=_photoImage alt="" src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fpostfiles12.naver.net%2F20110706_219%2Fohrak22_1309955630792wbPM6_JPEG%2F%25BB%25EF%25B0%25A2%25C7%25D4%25BC%25F63.jpg%3Ftype%3Dw2" width=200 height=134> 해답 - 피타고라스의 정리를 사용하여 빗변의 길이를 구한다. <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); WIDTH: 245px; HEIGHT: 27px; BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0)" id=se_object_1376621387547 class=__se_object src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fimages.se2.naver.com%2Fsmedit%2F2011%2F7%2F6%2Fgps9rlrt38i0c8.jpg" width=245 height=27> <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); WIDTH: 108px; HEIGHT: 36px; BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0)" id=se_object_1376621333294 class=__se_object src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fimages.se2.naver.com%2Fsmedit%2F2011%2F7%2F6%2Fgps9rrkhfxt7ny.jpg" width=108 height=36> <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); WIDTH: 110px; HEIGHT: 36px; BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0)" id=se_object_1376621373147 class=__se_object src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fimages.se2.naver.com%2Fsmedit%2F2011%2F7%2F6%2Fgps9rxsb974h28.jpg" width=110 height=36> <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); WIDTH: 110px; HEIGHT: 36px; BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0)" id=se_object_1376621318554 class=__se_object src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fimages.se2.naver.com%2Fsmedit%2F2011%2F7%2F6%2Fgps9s3x0usb9qn.jpg" width=110 height=36>     예제 2 다음 직삼각형의 밑변의 길이 a 값 구하기 <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0); CURSOR: pointer; rwidth: 150px; rheight: 261px" id=20110706_164/ohrak22_1309953250389fnulA_JPEG/%BB%EF%B0%A2%C7%D4%BC%F64.jpg class=_photoImage alt="" src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fpostfiles5.naver.net%2F20110706_164%2Fohrak22_1309953250389fnulA_JPEG%2F%25BB%25EF%25B0%25A2%25C7%25D4%25BC%25F64.jpg%3Ftype%3Dw2" width=150 height=261> 해답 <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); WIDTH: 93px; HEIGHT: 36px; BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0)" id=se_object_1376621391039 class=__se_object src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fimages.se2.naver.com%2Fsmedit%2F2011%2F7%2F6%2Fgps9saojh9c6lh.jpg" width=93 height=36> <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); WIDTH: 103px; HEIGHT: 18px; BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0)" id=se_object_1376621368479 class=__se_object src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fimages.se2.naver.com%2Fsmedit%2F2011%2F7%2F6%2Fgps9sgd3ime6rq.jpg" width=103 height=18> <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); WIDTH: 72px; HEIGHT: 18px; BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0)" id=se_object_1376621328855 class=__se_object src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fimages.se2.naver.com%2Fsmedit%2F2011%2F7%2F6%2Fgps9smvgwhl1v2.jpg" width=72 height=18> <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); WIDTH: 40px; HEIGHT: 18px; BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0)" id=se_object_1376621404366 class=__se_object src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fimages.se2.naver.com%2Fsmedit%2F2011%2F7%2F6%2Fgps9st0t7c2q0k.jpg" width=40 height=18>   예제 3 다음 직삼각형의 <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); WIDTH: 11px; HEIGHT: 18px; BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0)" id=se_object_1376621373351 class=__se_object src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fimages.se2.naver.com%2Fsmedit%2F2011%2F7%2F7%2Fgpt0bloamxhpz1.jpg" width=11 height=18> 값 구하기 <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0); CURSOR: pointer; rwidth: 250px; rheight: 269px" id=20110706_119/ohrak22_1309953544460oSBai_JPEG/%BB%EF%B0%A2%C7%D4%BC%F65.jpg class=_photoImage alt="" src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fpostfiles8.naver.net%2F20110706_119%2Fohrak22_1309953544460oSBai_JPEG%2F%25BB%25EF%25B0%25A2%25C7%25D4%25BC%25F65.jpg%3Ftype%3Dw2" width=250 height=269> <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); WIDTH: 107px; HEIGHT: 36px; BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0)" id=se_object_1376621362631 class=__se_object src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fimages.se2.naver.com%2Fsmedit%2F2011%2F7%2F6%2Fgps9t0pqpd40we.jpg" width=107 height=36> <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); WIDTH: 86px; HEIGHT: 23px; BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0)" id=se_object_1376621397392 class=__se_object src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fimages.se2.naver.com%2Fsmedit%2F2011%2F7%2F6%2Fgps9t6vr4gofwq.jpg" width=86 height=23> <IMG style="BORDER-BOTTOM-COLOR: rgb(0,0,0); BORDER-TOP-COLOR: rgb(0,0,0); WIDTH: 47px; HEIGHT: 18px; BORDER-RIGHT-COLOR: rgb(0,0,0); BORDER-LEFT-COLOR: rgb(0,0,0)" id=se_object_1376621319551 class=__se_object src="https://img1.daumcdn.net/relay/cafe/original/?fname=http%3A%2F%2Fimages.se2.naver.com%2Fsmedit%2F2011%2F7%2F6%2Fgps9tcf95tty83.jpg" width=47 height=18>   각을 알고 있을 경우에는 사인, 코사인, 탄젠트 함수를 그대로 사용하고,  각을 구하고 싶으면 역 삼각함수를 사용한다 (asin, acos, atan )</DIV>