Question

在三角形ABC,已知a=2根号2,b=2根号3,C=15°,解此三角形

Answer 1

cos15=cos(45-30)=cos45cos30+sin45sin30=(√6+√2)/4c²=a²+b²-2abcosC=4+8-8√2*(√6+√2)/4=12-4√3-4=8-2√12=(√6-√2)²c=√6-√2sin15=sin(45-30)=sin45cos30-cos45sin30=(√6-√2)/4a/sin...