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if tan A=24/7 and 180°

来源:学生作业帮 编辑:作业帮 分类:综合作业 时间:2024/05/14 01:10:58
if tan A=24/7 and 180°
-3/5
再问: 过程能写出来吗?摆脱啦~
再答: tan is opposite over adjacent, so we can let opposite = 24 and adjacent = 7 but since the angle is in quadrant 3, so opposite = -24 and adjacent = -7 due to pythagorean theorem, hypotenuse = 25. so, cos(A) = adjacent over hypotenuse = -7/25 double-angle formula: cos(x) = 2cos(x/2)^2-1 so: cos(A/2)^2 = (cos(A)+1)/2 = 9/25 so: cos(A/2) = 3/5 or -3/5 since 180°