Menjawab:
Lihat proses solusi di bawah ini:
Penjelasan:
Pertama, tulis ulang ekspresi di bawah radikal sebagai:
Sekarang, gunakan aturan radikal ini untuk menulis ulang ekspresi radikal dan menyelesaikan penyederhanaan:
Apa itu (sqrt (5+) sqrt (3)) / (sqrt (3+) sqrt (3+) sqrt (5)) - (sqrt (5-) sqrt (3)) / (sqrt (3+) sqrt (3-) sqrt (5))?
2/7 Kita ambil, A = (sqrt5 + sqrt3) / (sqrt3 + sqrt3 + sqrt5) - (sqrt5-sqrt3) / (sqrt3 + sqrt3-sqrt5) = (sqrt5 + sqrt3) / (2sqrt3 + sqrt5) - (sqrt5) -sqrt3) / (2sqrt3-sqrt5) = (sqrt5 + sqrt3) / (2sqrt3 + sqrt5) - (sqrt5-sqrt3) / (2sqrt3-sqrt5) = ((sqrt5 + sqrt3) (2sqrt3-sqrt5) - (sqrt5-sqrt5) - (sqrt5-sqrt5) ) (2sqrt3 + sqrt5)) / ((2sqrt3 + sqrt5) (2sqrt3-sqrt5) = ((2sqrt15-5 + 2 * 3-sqrt15) - (2sqrt15 + 5-2 * 3-sqrt15)) / ((2sqrt3) ^ 2- (sqrt5) ^ 2) = (batal (2sqrt15) -5 + 2 * 3cancel (-sqrt15) - batalkan (2sqrt15) -5 + 2 * 3 + batal (sqrt15)) / (12-5) = ( -10 + 12) / 7 = 2/7 Perhatikan bahwa, jika dalam penyebutnya adala
Sederhanakan ungkapannya ?: 1 / (sqrt (144) + sqrt (145)) + 1 / (sqrt (145) + sqrt (146)) + ... + 1 / (sqrt (168) + sqrt (169))
1 Perhatikan pertama bahwa: 1 / (sqrt (n + 1) + sqrt (n)) = (sqrt (n + 1) -sqrt (n)) / ((sqrt (n + 1) + sqrt (n)) ( sqrt (n + 1) -sqrt (n)) warna (putih) (1 / (sqrt (n + 1) + sqrt (n))) = (sqrt (n + 1) -sqrt (n)) / (( n + 1) -n) warna (putih) (1 / (sqrt (n + 1) + sqrt (n))) = sqrt (n + 1) -sqrt (n) Jadi: 1 / (sqrt (144) + sqrt (145)) + 1 / (sqrt (145) + sqrt (146)) + ... + 1 / (sqrt (168) + sqrt (169)) = (sqrt (145) -sqrt (144)) + (sqrt (146) -sqrt (145)) + ... + (sqrt (169) -sqrt (168)) = sqrt (169) -sqrt (144) = 13-12 = 1
(sqrt 5 - sqrt 7) (sqrt 5 - sqrt 8) Lipat gandakan dan Sederhanakan?
(sqrt5-sqrt7) (sqrt5-sqrt8) = warna (biru) (5-2sqrt10-sqrt35 + 2sqrt14 (sqrt5-sqrt7) (sqrt5-sqrt7) (sqrt5-sqrt8) Gunakan metode FOIL. http://en.wikipedia.org/wiki/ FOIL_method (sqrt5sqrt5) - (sqrt5sqrt8) - (sqrt5sqrt7) + (sqrt7sqrt8) Sederhanakan. 5-sqrt40-sqrt35 + sqrt56 Perdana pisahkan radicand. 5-sqrt (2 * 2 * 2 * 5) -sqrt (5 * 7) + sqrt (2 * 2 * 2 * 7) Sederhanakan. 5-2sqrt10-sqrt35 + 2sqrt14