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Jika ∣ ∣ ​ a ∣ ∣ ​ = 1 , ∣ ∣ ​ b ∣ ∣ ​ = 4 dan a ⋅ b = 3 , maka ∣ ∣ ​ 2 a − b ∣ ∣ ​ = ...

Jika ,  dan , maka   

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A. Armanda

Master Teacher

Mahasiswa/Alumni Universitas Indraprasta PGRI

Jawaban terverifikasi

Jawaban

.

 table attributes columnalign right center left columnspacing 0px end attributes row blank blank cell open vertical bar 2 a with rightwards arrow on top minus b with rightwards arrow on top close vertical bar end cell end table table attributes columnalign right center left columnspacing 0px end attributes row blank equals blank end table table attributes columnalign right center left columnspacing 0px end attributes row blank blank 2 end table table attributes columnalign right center left columnspacing 0px end attributes row blank blank cell square root of 2 end cell end table.

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Pembahasan

Panjang dapat dituliskan sebagai berikut. Berdasarkan yang diketahui, maka: Jika dan , maka: Sehingga, Jadi, .

Panjang a with rightwards arrow on top equals open parentheses table row cell a subscript 1 end cell row cell a subscript 2 end cell end table close parentheses dapat dituliskan sebagai berikut.

open vertical bar a with rightwards arrow on top close vertical bar equals square root of a subscript 1 squared plus a subscript 2 squared end root 

Berdasarkan yang diketahui, maka:

table attributes columnalign right center left columnspacing 0px end attributes row cell open vertical bar a with rightwards arrow on top close vertical bar end cell equals cell square root of a subscript 1 squared plus a subscript 2 squared end root end cell row 1 equals cell square root of a subscript 1 squared plus a subscript 2 squared end root end cell row cell 1 squared end cell equals cell open parentheses square root of a subscript 1 squared plus a subscript 2 squared end root close parentheses squared end cell row 1 equals cell a subscript 1 squared plus a subscript 2 squared end cell row cell open vertical bar b with rightwards arrow on top close vertical bar end cell equals cell square root of b subscript 1 squared plus b subscript 2 squared end root end cell row 4 equals cell square root of b subscript 1 squared plus b subscript 2 squared end root end cell row cell 4 squared end cell equals cell open parentheses square root of b subscript 1 squared plus b subscript 2 squared end root close parentheses squared end cell row 16 equals cell b subscript 1 squared plus b subscript 2 squared end cell end table 

Jika a with rightwards arrow on top equals open parentheses table row cell a subscript 1 end cell row cell a subscript 2 end cell end table close parentheses dan b with rightwards arrow on top equals open parentheses table row cell b subscript 1 end cell row cell b subscript 2 end cell end table close parentheses, maka:

a with rightwards arrow on top times b with rightwards arrow on top equals a subscript 1 b subscript 1 plus a subscript 2 b subscript 2 

Sehingga,

table attributes columnalign right center left columnspacing 0px end attributes row cell open vertical bar 2 a with rightwards arrow on top minus b with rightwards arrow on top close vertical bar end cell equals cell square root of open parentheses 2 a subscript 1 minus b subscript 1 close parentheses squared plus open parentheses 2 a subscript 2 minus b subscript 2 close parentheses squared end root end cell row blank equals cell square root of 4 a subscript 1 squared minus 4 a subscript 1 b subscript 1 plus b subscript 1 squared plus 4 a subscript 2 squared minus 4 a subscript 2 b subscript 2 plus b subscript 2 squared end root end cell row blank equals cell square root of 4 open parentheses a subscript 1 squared plus a subscript 2 squared close parentheses minus 4 open parentheses a subscript 1 b subscript 1 plus a subscript 2 b subscript 2 close parentheses plus b subscript 1 squared plus b subscript 2 squared end root end cell row blank equals cell square root of 4 times 1 minus 4 times 3 plus 16 end root end cell row blank equals cell square root of 4 minus 12 plus 16 end root end cell row blank equals cell square root of 8 end cell row blank equals cell square root of 4 times 2 end root end cell row blank equals cell 2 square root of 2 end cell end table 

Jadi, table attributes columnalign right center left columnspacing 0px end attributes row blank blank cell open vertical bar 2 a with rightwards arrow on top minus b with rightwards arrow on top close vertical bar end cell end table table attributes columnalign right center left columnspacing 0px end attributes row blank equals blank end table table attributes columnalign right center left columnspacing 0px end attributes row blank blank 2 end table table attributes columnalign right center left columnspacing 0px end attributes row blank blank cell square root of 2 end cell end table.

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