谁帮我解这条数学题(高中)△ABC中,3sinA+4cosB=6,4sinB+3cosA=1,则∠C的大小为?,-.___./ | ' \ ( ) 0 \_/-,,----' ==== // / \-'~; (O)/ __/~| / |=( _____| (_________|
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![谁帮我解这条数学题(高中)△ABC中,3sinA+4cosB=6,4sinB+3cosA=1,则∠C的大小为?,-.___./ | ' \ ( ) 0 \_/-,,----' ==== // / \-'~; (O)/ __/~| / |=( _____| (_________|](/uploads/image/z/956819-11-9.jpg?t=%E8%B0%81%E5%B8%AE%E6%88%91%E8%A7%A3%E8%BF%99%E6%9D%A1%E6%95%B0%E5%AD%A6%E9%A2%98%EF%BC%88%E9%AB%98%E4%B8%AD%EF%BC%89%E2%96%B3ABC%E4%B8%AD%2C3sinA%2B4cosB%3D6%2C4sinB%2B3cosA%3D1%2C%E5%88%99%E2%88%A0C%E7%9A%84%E5%A4%A7%E5%B0%8F%E4%B8%BA%3F%2C-.___.%2F+%7C+%27+%5C+%28+%29+0+%5C_%2F-%2C%2C----%27+%3D%3D%3D%3D+%2F%2F+%2F+%5C-%27%7E%3B+%28O%29%2F+__%2F%7E%7C+%2F+%7C%3D%28+_____%7C+%28_________%7C)
谁帮我解这条数学题(高中)△ABC中,3sinA+4cosB=6,4sinB+3cosA=1,则∠C的大小为?,-.___./ | ' \ ( ) 0 \_/-,,----' ==== // / \-'~; (O)/ __/~| / |=( _____| (_________|
谁帮我解这条数学题(高中)
△ABC中,3sinA+4cosB=6,4sinB+3cosA=1,则∠C的大小为?
,-.___.
/ | ' \
( ) 0
\_/-,,----'
==== //
/ \-'~; (O)
/ __/~| / |
=( _____| (_________|
谁帮我解这条数学题(高中)△ABC中,3sinA+4cosB=6,4sinB+3cosA=1,则∠C的大小为?,-.___./ | ' \ ( ) 0 \_/-,,----' ==== // / \-'~; (O)/ __/~| / |=( _____| (_________|
(1)^2+(2)^2
9+16+24(sin(A+B))=36+1
sin(A+B)=1/2
A+B=30 或者150.
如果A3/2*根号3>1 矛盾.
A+B=150
C=30
对两个算式分别求平方,然后再把两个新算式加起来.就能得到sin(A+B),不就得到你要的答案了.
两个式子两边平方
然后相加起来
化简得
25+24sin(A+B)=37
A+B=30或150
则C=150或30