For positive integer n, define f(n) = n + (16+5n-3n²)/(4n+3n²) + (32+n-3n²)/(8n+3n²) + (48-3n-3n²)/(12n+3n²) + ... + (25n-7n²)/7n². Then, the value of lim_(n → ∞) f(n) is equal to
f(n)=n+4n+3n216+5n−3n2+8n+3n232+n−3n2+…+7n225n−7n2
limn→∞f(n)=?
Tk=4kn+3n216k+(9−4k)n−3n2,k=1,2,…,n
k=n: 4n2+3n216n+(9−4n)n−3n2=7n225n−7n2 ✓
Tk=−1+4kn+3n216k+9n=−1+n(3n+4k)16k+9n
f(n)=n+∑k=1nTk=n−n+∑k=1nn(3n+4k)16k+9n
=∑k=1nn(3n+4k)16k+9n
=n1∑k=1n3+4nk16nk+9=n1∑k=1ng(nk)
g(x)=3+4x16x+9
limn→∞f(n)=∫013+4x16x+9dx
3+4x16x+9=4−4x+33
∫01(4−4x+33)dx=[4x−43ln(4x+3)]01
=4−43ln(37)
4−43loge(37)(2)