Given a triangle with a=11, b=14, and α=15°, what is (are) the possible length(s) of c?
Given a triangle with a=11, b=14, and α=15∘, what is (are) the possible length(s) of c?
a2=b2+c2−2bc⋅cos(α)c2−2b⋅cos(α)⋅c+b2−a2=0 Ac2+Bc+C=0c=−B±√B2−4AC2A c2−2b⋅cos(α)⋅c+b2−a2=0A=1B=−2b⋅cos(α)C=b2−a2c=2b⋅cos(α)±√(2b⋅cos(α))2−4(b2−a2)2c=b⋅cos(α)±√[b⋅cos(α)]2−(b2−a2)c=b⋅cos(α)±√b2⋅[cos2(α)−1]+a2c=b⋅cos(α)±√b2⋅[1−sin2(α)−1]+a2c=b⋅cos(α)±√a2−b2⋅sin2(α)a=11b=14α=15∘c=14⋅cos(15∘)±√112−142⋅sin2(15∘)c=14⋅0.96592582629±√107.870489571c=13.5229615680±10.3860719028c1=13.5229615680+10.3860719028c1=23.9090334709c2=13.5229615680−10.3860719028c2=3.13688966521
check:
c1⋅c2=(b−a)(b−a+2a)c1⋅c2=(b−a)(b+a)c1⋅c2=b2−a2a=11b=14c1⋅c2=142−112c1⋅c2=75c1⋅c2=23.9090334709⋅3.13688966521c1⋅c2=75 Okay
Given a triangle with a=11, b=14, and α=15∘, what is (are) the possible length(s) of c?
a2=b2+c2−2bc⋅cos(α)c2−2b⋅cos(α)⋅c+b2−a2=0 Ac2+Bc+C=0c=−B±√B2−4AC2A c2−2b⋅cos(α)⋅c+b2−a2=0A=1B=−2b⋅cos(α)C=b2−a2c=2b⋅cos(α)±√(2b⋅cos(α))2−4(b2−a2)2c=b⋅cos(α)±√[b⋅cos(α)]2−(b2−a2)c=b⋅cos(α)±√b2⋅[cos2(α)−1]+a2c=b⋅cos(α)±√b2⋅[1−sin2(α)−1]+a2c=b⋅cos(α)±√a2−b2⋅sin2(α)a=11b=14α=15∘c=14⋅cos(15∘)±√112−142⋅sin2(15∘)c=14⋅0.96592582629±√107.870489571c=13.5229615680±10.3860719028c1=13.5229615680+10.3860719028c1=23.9090334709c2=13.5229615680−10.3860719028c2=3.13688966521
check:
c1⋅c2=(b−a)(b−a+2a)c1⋅c2=(b−a)(b+a)c1⋅c2=b2−a2a=11b=14c1⋅c2=142−112c1⋅c2=75c1⋅c2=23.9090334709⋅3.13688966521c1⋅c2=75 Okay