Diketahui barisan aritmatika -12, -9½, -7, -4½, -2,........ tentukan a. beda barisan b. suku ke-10

<p>Diketahui barisan aritmatika : -12 ; -9½ ;-7 ; -4½ ; -2.</p><p>Ditanya : a. Beda barisan</p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;b. Suku ke 10.</p><p>Jawab :&nbsp;</p><p>a. Pada soal ini, beda barisan dapat dilihat dengan cara mengurangi selisih tiap angka pada barisan.&nbsp;</p><p>(-12)-(-9½) = 2½.</p><p>Jadi, beda dari barisan tersebut adalah 2½.</p><p>b. Rumus suku ke-n yaitu :</p><p><strong>Un = a+(n-1)b</strong></p><p><strong>Keterangan : Un = suku-...n</strong></p><p><strong>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; a = suku pertama&nbsp;</strong></p><p><strong>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; n = jumlah suku&nbsp;</strong></p><p>&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;<strong>b = beda.</strong></p><p><strong>Un = a+(n-1)b</strong></p><p><strong>U₁₀= -12 + (10-1).(2½)</strong></p><p><strong>U₁₀= -12 + (9).(2½)</strong></p><p><strong>U₁₀= -12 + (22½)</strong></p><p><strong>U₁₀= 10½</strong></p><p>&nbsp;</p><p>Jadi, suku-₁₀adalah 10½</p><p>&nbsp;</p><p>&nbsp;</p>