cos²α-sin²β/sin²αsin² β=cot² α cot² β -1
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/05 22:18:19
![cos²α-sin²β/sin²αsin² β=cot² α cot² β -1](/uploads/image/z/3015464-32-4.jpg?t=cos%26%23178%3B%CE%B1-sin%26%23178%3B%CE%B2%2Fsin%26%23178%3B%CE%B1sin%26%23178%3B+%CE%B2%3Dcot%26%23178%3B+%CE%B1+cot%26%23178%3B+%CE%B2+-1)
cos²α-sin²β/sin²αsin² β=cot² α cot² β -1
cos²α-sin²β/sin²αsin² β=cot² α cot² β -1
cos²α-sin²β/sin²αsin² β=cot² α cot² β -1
左=cot² α cot² β -1=cos²αcos²β/sin²αsin²β-1
=[cos²αcos²β-sin²αsin²β]/sin²αsin²β
=[cos²α(1-sin²β)-sin²β(1-cos²α)]/sin²αsin²β
=cos²α-sin²β/sin²αsin² β=右