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2J. S. Sumner, A. A. Jagers, Micheal Vowe, and jean Anglesio, Inequalities Involving Trigonometric Functions[J], The American Mathematical Monthly, 1991, 98(3):264-267.
1Wilker J.B., E3301[J], The American Mathematical Monthly, 1989, 96(1):55.
2Sumner J. S., Jagers A. A., Vowe M., and Anglesio J., Inequalities involving trigonometric functions[J],The American Mathematical Monthly, 1991, 98(3):264 - 267.
3王竹溪 郭敦仁.特殊函数概论[M].科学出版社,1979.729.
4J.B. Wilker. E3306[J]. The American Mathematical Monthly,1989,96(1) :55.
5J.S. Sumner, A. A. Jagers,M. Vowe,and J. Anglesio Inequalities involving trigonometric function[J]. The American Mathematical Monthly, 1991,98 (3): 264-267.
