WEBVTT

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Sekarang, kita akan kaji kaitan antara 
2 garisan selari.

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Ini sangat membantu dlm pengiraan kita nanti.

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Terutamanya utk selesaikan 
persamaan garisan lurus.

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Cth: y1 iaitu persamaan garis lurus 1.

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dan y2.

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Perhatikan apa persamaan atau ciri-ciri 
sepunya kedua-dua garisan ini?

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Jika garisan selari, 
maka mesti wujud persamaan.

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Kedua-dua garisan sama arah,
atau sama condong.


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Atau kita sebut sbg sama kecerunan.

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Jika garisan 1 selari dgn garisan 2,

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( // ialah simbol selari)

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maka kecerunan, m1 = m2

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Jika m1 = 4, 
maka m2 = 4 juga.

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Jika m1 = -5,
maka m2 = -5

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Ada 1 lagi jenis garisan iaitu
garisan serenjang.

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Maksudnya ia membentuk sudut 90°.

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Ini λ1 dan λ2.

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Apakah hubungan kedua-dua λ?

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Apabila λ1 serenjang (⊥) dgn λ2,

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wujud 1 kaitan antara mereka.

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Boleh anda teka?

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Jika garisan adalah serenjang (⊥),

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maka kecerunan, 
m1 x m2 = -1

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Jadi, formula kecerunan, m utk 
garis serenjang:

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m1m2= -1

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Tapi ada jalan kira yg lebih ringkas

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utk cari kecerunan garis serenjang.

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Anda nak tahu?

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Utk garis serenjang,
jika m1 = 3/4,

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m2 ialah songsangan bg m1.

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Anda songsangkan nilai m1,

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maka m2 = 4/3

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Tukar tanda nilai.

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Jika m1 = +ve,
maka m2 = -ve

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Cth lagi:
jika m1 = -2/5

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maka songsangan nya:

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m2= 5/2

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Jika m1=7,

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nilai sebenar ialah 7/1,

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maka m2=1/7

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tukar +ve ke -ve.

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Kesimpulannya, inilah hubung kait antara

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garisan Selari ( // )

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dan garisan Serenjang (⊥).