优质解答
1.设BC为x(自己画个图)
x^2+4x^2=4
x=2√5/5
∴b=4√5/5
sinA=√5/5
cosA=2√5/5
2.设AC为4x,BC为5x
25x^2-16x^2=144
x=4
AC=16,BC=20
tanA=4分之3
3.2分之6根号69
1.设BC为x(自己画个图)
x^2+4x^2=4
x=2√5/5
∴b=4√5/5
sinA=√5/5
cosA=2√5/5
2.设AC为4x,BC为5x
25x^2-16x^2=144
x=4
AC=16,BC=20
tanA=4分之3
3.2分之6根号69