1. We start with the given equation:
m3=9n4+170n2+289
We can rewrite the right-hand side as a product of two polynomials:
m3=(9n2+17)(n2+17)
2. Next, we consider the case where 17 divides n. If 17∣n, then n=17k for some integer k. Substituting n=17k into the equation, we get:
m3=9(17k)4+170(17k)2+289
Simplifying, we have:
m3=9⋅174k4+170⋅172k2+289
Since 173∣9⋅174k4 and 173∣170⋅172k2, it follows that 173∣m3. Therefore, 17∣m. Let m=17p for some integer p. Substituting m=17p into the equation, we get:
(17p)3=9⋅174k4+170⋅172k2+289
Simplifying, we have:
173p3=9⋅174k4+170⋅172k2+289
Dividing both sides by 173, we get:
p3=9⋅17k4+170k2+173289
Since 173289 is not an integer, this leads to a contradiction. Hence, 17 does not divide n.
3. Now, we consider the case where 17 and n are coprime. Let gcd(9n2+17,n2+17)=d. It follows that d∣(9n2+17)−9(n2+17):
d∣(9n2+17)−9(n2+17)=9n2+17−9n2−153=−136
Therefore, d∣136. The divisors of 136 are 1,2,4,8,17,34,68,136.
4. If d=1, assume we have 9n2+17=a3 and n2+17=b3 for positive integers a and b. Considering modulo 7:
9n2+17≡2n2+3(mod7)
n2+17≡n2+3(mod7)
Since a3≡b3(mod7), we need 2n2+3≡n2+3(mod7), which implies n2≡0(mod7). Thus, 7∣n, contradicting that 17 and n are coprime.
5. If d=2, we have 8∣(9n2+17)(n2+17). Considering modulo 4:
9n2+17≡n2+1(mod4)
n2+17≡n2+1(mod4)
Since 8∣(n2+1)(n2+1), we need n2≡3(mod4), which is impossible since n2≡0,1(mod4).
6. If d=4 or d=8, we will get a contradiction by considering modulo 4:
9n2+17≡n2+1(mod4)
n2+17≡n2+1(mod4)
Since 4∣(n2+1)(n2+1), we need n2≡3(mod4), which is impossible.
Therefore, there are no positive integers m and n satisfying the equation m3=9n4+170n2+289.