20 15 Jinshan Grade 3 Mathematics Module 2

(1) From the meaning of the question: 9a? 3b+c=0a+b+c=0c=3，

Solution: a =? 1b=？ 2c=3，

∴y=-x2-2x+3；

(2)y=-x2-2x+3=-(x+ 1)2+4，

∴P(- 1,4)，

∴PA=25,PC=2,AC=32，

∫PA2 = PC2+AC2

∴∠PCA=90，

∴tan∠pac=pcac=232= 13；

(3) The analytical formula of linear AC is: y=x+3,

The analytical formula of linear AP is y=2x+6,

The analytical formula of linear PC is: y=-x+3,

When AC is the diagonal of parallelogram:

PC∨AM，AP∨CM，

∴ Using two parallel lines with equal values of k, we can get:

The analytical formula of the straight line MC is y=2x+3,

The analytical formula of linear AM is y=-x-3,

∴M(-2,- 1)，

When PC is the diagonal of a parallelogram, ∴ m (2 2,7) can be obtained in the same way.

When AP is the diagonal of a parallelogram: ∴ m (-4, 1),

∴M(-2,-1) or m (2,7) or m (-4, 1).