Question

在三角形ABC中,若角B=45度,AC=2倍根号2,AB=2,则三角形ABC的面积是（ ）拜托各位了 3Q

Answer 1

AC^2=AB^2+BC^2-2BC*ABcos45° 8=4+BC^2-2√ 2BC BC^2-2√ 2BC-4=0 BC=[2√ 2+√ (8+16)]/2=√ 2+√ 6 BC=[2√ 2-√ (8+16)]/2=√ 2-√ 6