let p,q,r,s, and t be roots of x^5-160x-128 = 0. Compute p^5 + q^5 + r^5 + s^5 + t^5
Here are the roots here......http://www.wolframalpha.com/input/?i=solve+x^5++-160x+-128+%3D+0
Just assign each "real" root to a different variable, take the 5th power of each, and sum your answers.
P.S. (The sum of the non-real roots raised to the 5th power is about 160 .....it actually may be 160 exactly....I used Wolfram Alpha to find the roots....and they may have been "rounded")
Here are the roots here......http://www.wolframalpha.com/input/?i=solve+x^5++-160x+-128+%3D+0
Just assign each "real" root to a different variable, take the 5th power of each, and sum your answers.
P.S. (The sum of the non-real roots raised to the 5th power is about 160 .....it actually may be 160 exactly....I used Wolfram Alpha to find the roots....and they may have been "rounded")
Because x5 = 160x + 128 the sum of the fifth powers of the five roots will be 160*(p+q+r+s+t) + 5*128
Numerically, the p+q+r+s+t seems to be 0 (I used Mathcad's symbolic calculator with 200 significant figures and got a number around 10-204 for the sum). If so then the sum p5+q5+r5+s5+t5 = 5*128 = 640.