![Apakah sifar f (x) = 31x ^ 4 +57 -13x ^ 2? Apakah sifar f (x) = 31x ^ 4 +57 -13x ^ 2?](https://img.go-homework.com/img/algebra/what-are-the-zeros-of-9-15t-4.9t2.jpg)
Jawapan:
#x = + -sqrt ((13 + -i sqrt (6899)) / 62) #
Penjelasan:
#f (x) = 31x ^ 4 + 57-13x ^ 2 #
# = 31 (x ^ 2) ^ 2-13 (x ^ 2) + 57 #
Menggunakan formula kuadratik, ini mempunyai akar:
# x ^ 2 = (13 + -sqrt (13 ^ 2- (4xx31xx57))) / (2 * 31) #
# = (13 + -sqrt (-6899)) / 62 #
# = (13 + -i sqrt (6899)) / 62 #
Jadi
#x = + -sqrt ((13 + -i sqrt (6899)) / 62) #