(√7+3)² = (r² -2)r² * cos(2Π/3) I have an answer, I just want to check my work against yours.
2006-07-29 11:21:28 · 3 answers · asked by Rockstar 6 in Science & Mathematics ➔ Mathematics
It's for a program I'm writing where i need some functions to occur, y = x + (this equation). I need to simplify.
2006-07-29 11:23:44 · update #1
(√7+3)² = (r² -2)r² * cos(2Π/3)
(√7+3)² = (r² -2)r² * (-0.5)
(7 + 6*√7 + 9) = (r² -2)r² * (-0.5)
(16 + 6*√7) = (r² -2)r² * (-0.5)
(32 + 12*√7) = (-r²)(r² -2)
-r^4 + 2r² - 32 - 12*√7 = 0
let R = r²
-R² + 2R - 32 - 12*√7 = 0
Quadratic equation
R = -2 +or- √[2² - 4*(-1)*(- 32 - 12*√7)]
R = -2 +or- √[4 - 128 - 48*√7]
R = -2 +or- √[124 - 48*√7]
r = +or- √[-2 +or- √(124 - 48*√7)]
2006-07-29 11:34:39 · answer #1 · answered by bogusman82 5 · 5⤊ 0⤋
What does the asterisk in front of the cos mean? If it means simply multiplication then Bogusman is correct in obtaining the quadratic equation in R but this equation,
R^2-2R+32+12sqrt7 =0
has only complex roots and so the quartic equation in r has four complex roots and no real solution.
2006-07-29 22:45:53 · answer #2 · answered by grsym 2 · 0⤊ 0⤋
yikes. i've only gotten so far as geometry... sorry! lol i can read it all, except for that one character that's almost a square, but not. lol i feel stupid. americans don't know any math!! and my school won't let me take pre-cal and algebra 2 next year! grrrrrrrrrrrrr
2006-07-29 18:26:12 · answer #3 · answered by Anonymous · 0⤊ 0⤋