在△ABC中,A=45度.B=60度.AB=2,求△ABC的面积.(成考09.24)
请用正弦定理.
可知(BC/SINA)=(AB/SINC),则
BC=(2X√2)/SIN(π-45-60)=(√2)/(√2/2X√3/2+√2/2+1/2)
我不明白接着为什么等于 (√2)/(√6+√2),下面还有分母2哪里去了.
=2(√3-1)
人气:200 ℃ 时间:2020-09-18 05:57:29
解答
BC/(√2/2)=2/[(√6+√2)/4],BC=4√2/(√6+√2)再分母有理化,得2(√3-1)
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