22° - Matemática

05/05/15

Equação fundamental da reta

2ºBimestre

|y-yo=m(x-x-o)|

1- Determine a equação da reta que passa pelo ponto A(-1,4) e tem coeficiente angular (m)=2.

        xo=-1 | yo=4 | m=2
        y-yo=m(x-xo)
        y-4=2.(x-(-1))
        y-4=2.(x+1)
        y-4=2x+2
        -2x+y-4-2=0^(-1)
        2x-y+4+2=0
        2x-y+6=0 

2- Determine a equação da reta que passa pelos pontos A(-1,-2) e B(5,2).

        m=y₂-y₁=2-(-2)=4^:2=2

              x₂-x₁  5-(-1)  6^:2  3

      A(-1,-2) -> y-yo=m.(x-xo)      B(5,2) -> y-yo=m.(x-xo)

        m=2         y+2=2(x+1)            m=2       y-2=2x-10  

              3                 3                           3                3   3

                         y+2=2x+2                              y-2=2x-10

                                  3    3                                          3

                         y+2=2x+2

                                     3                                 3y-6=2x-10

                                                                               3y-2x-6+10=0

                       3(y+2)=2x+2                           -2x+3y+4=0^(-1)

                       3y+6-2x-2=0                           2x-3y-4=0

                       -2x+3y+4=0^(-1)

                       2x-3y-4=0