cos[arccos3/5+ARCCOS(-12/13)]HELP HELP
问题描述:
cos[arccos3/5+ARCCOS(-12/13)]
HELP HELP
答
这个式子 首先要明白3/5 和12/13都是在常见直角三角形中的余弦值 一个是3 4 5一个是5 12 13,而-12/13则是5 12 13三角形中的5所对角的补角的余弦值,明白这个后,把3 4 5中4所对角设为A,那个补角设为B,它们的余弦值分别...
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