Roots of a Quartic polynomial with complex coefficients computed using symbolic solutions

The general form of the 4th degree equation (or [b]Quartic[/b]) is: ax⁴ + bx³ + cx² + dx + e = 0. Quartics have 4 roots. They are given by: #z1 = (-b) / (4a) - 1 / 2 sqrt(0ί + b² / (4a²) - 2c / (3a) + 2^(1 / 3) (c² - 3b d + 12a e) / (3a (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) + 1 / (3 * 2^(1 / 3) a) (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) - 1 / 2 sqrt(0ί + b² / (2a²) - 4c / (3a) - 2^(1 / 3) (c² - 3b d + 12a e) / (3a (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) - 1 / (3 * 2^(1 / 3) a) (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3) - ((-b³) / a³ + 4b c / a² - 8d / a) / (4sqrt(0ί + b² / (4a²) - 2c / (3a) + 2^(1 / 3) (c² - 3b d + 12a e) / (3a (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) + 1 / (3 * 2^(1 / 3) a) (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)))); #z2 = (-b) / (4a) - 1 / 2 sqrt(0ί + b² / (4a²) - 2c / (3a) + 2^(1 / 3) (c² - 3b d + 12a e) / (3a (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) + 1 / (3 * 2^(1 / 3) a) (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) + 1 / 2 sqrt(0ί + b² / (2a²) - 4c / (3a) - 2^(1 / 3) (c² - 3b d + 12a e) / (3a (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) - 1 / (3 * 2^(1 / 3) a) (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3) - ((-b³) / a³ + 4b c / a² - 8d / a) / (4sqrt(0ί + b² / (4a²) - 2c / (3a) + 2^(1 / 3) (c² - 3b d + 12a e) / (3a (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) + 1 / (3 * 2^(1 / 3) a) (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)))); #z3 = (-b) / (4a) + 1 / 2 sqrt(0ί + b² / (4a²) - 2c / (3a) + 2^(1 / 3) (c² - 3b d + 12a e) / (3a (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) + 1 / (3 * 2^(1 / 3) a) (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) - 1 / 2 sqrt(0ί + b² / (2a²) - 4c / (3a) - 2^(1 / 3) (c² - 3b d + 12a e) / (3a (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) - 1 / (3 * 2^(1 / 3) a) (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3) + ((-b³) / a³ + 4b c / a² - 8d / a) / (4sqrt(0ί + b² / (4a²) - 2c / (3a) + 2^(1 / 3) (c² - 3b d + 12a e) / (3a (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) + 1 / (3 * 2^(1 / 3) a) (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)))); #z4 = (-b) / (4a) + 1 / 2 sqrt(0ί + b² / (4a²) - 2c / (3a) + 2^(1 / 3) (c² - 3b d + 12a e) / (3a (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) + 1 / (3 * 2^(1 / 3) a) (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) + 1 / 2 sqrt(0ί + b² / (2a²) - 4c / (3a) - 2^(1 / 3) (c² - 3b d + 12a e) / (3a (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) - 1 / (3 * 2^(1 / 3) a) (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3) + ((-b³) / a³ + 4b c / a² - 8d / a) / (4sqrt(0ί + b² / (4a²) - 2c / (3a) + 2^(1 / 3) (c² - 3b d + 12a e) / (3a (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)) + 1 / (3 * 2^(1 / 3) a) (2c³ - 9b c d + 27a d² + 27b² e - 72a c e + sqrt(0ί - 4(c² - 3b d + 12a e)³ + (2c³ - 9b c d + 27a d² + 27b² e - 72a c e)²))^(1 / 3)))).

 

Roman Chijner

 
Resource Type
Activity
Tags
cardan  cubic  equation  polynomial  quartic  roots  tutorial 
Target Group (Age)
3 – 19+
Language
English
 
 
 
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