(n is a natural number)
Hello once again Jake
Prove by induction (n is a nattural number)
\(1+\frac{1}{4}+\frac{1}{9}..........+\frac{1}{n^2}<2-\frac{1}{n}\\\)
Step 1
Prove true for n=1
LHS = 1/1^2 = 1
RHS = 2-1/1 = 1 LHS
Therefore true for n=1
Step 2
Assume true for n=k
\(1+\frac{1}{4}+\frac{1}{9}..........+\frac{1}{k^2}<2-\frac{1}{k}\\\)
Now prove true for n=k+1
that is, prove
\(1+\frac{1}{4}+\frac{1}{9}..........+\frac{1}{k^2}+\frac{1}{(k+1)^2}<2-\frac{1}{k+1}\\ 1+\frac{1}{4}+\frac{1}{9}..........+\frac{1}{k^2}+\frac{1}{(k+1)^2}<2-\frac{k(k+1)}{k(k+1)^2}\\ 1+\frac{1}{4}+\frac{1}{9}..........+\frac{1}{k^2}+\frac{1}{(k+1)^2}<2-\frac{k^2+1}{k(k+1)^2}\\ \\ LHS<(2-\frac{1}{k})+\frac{1}{(k+1)^2}\\ LHS<2-\left(\frac{1}{k}-\frac{1}{(k+1)^2}\right)\\ LHS<2-\left(\frac{(k+1)^2}{k(k+1)^2}-\frac{k}{k(k+1)^2}\right)\\ LHS<2-\left(\frac{k^2+k+1}{k(k+1)^2}\right)\\ LHS<2-\frac{k^2+1}{k(k+1)^2}-\frac{k}{k(k+1)^2}\\ therefore\\ LHS<2-\frac{k^2+1}{k(k+1)^2}\\ LHS<2-\frac{1}{k+1}\\ \)
Therefore, if true for n=k then it must be true for n=k+1
Step 3
Since true for n=1, it must be true for n=2
Since true for n=2 it must be true for n=3, n=4,n=5, etc.
Therefore true for al n where \(n\in N\)
Hello once again Jake
Prove by induction (n is a nattural number)
\(1+\frac{1}{4}+\frac{1}{9}..........+\frac{1}{n^2}<2-\frac{1}{n}\\\)
Step 1
Prove true for n=1
LHS = 1/1^2 = 1
RHS = 2-1/1 = 1 LHS
Therefore true for n=1
Step 2
Assume true for n=k
\(1+\frac{1}{4}+\frac{1}{9}..........+\frac{1}{k^2}<2-\frac{1}{k}\\\)
Now prove true for n=k+1
that is, prove
\(1+\frac{1}{4}+\frac{1}{9}..........+\frac{1}{k^2}+\frac{1}{(k+1)^2}<2-\frac{1}{k+1}\\ 1+\frac{1}{4}+\frac{1}{9}..........+\frac{1}{k^2}+\frac{1}{(k+1)^2}<2-\frac{k(k+1)}{k(k+1)^2}\\ 1+\frac{1}{4}+\frac{1}{9}..........+\frac{1}{k^2}+\frac{1}{(k+1)^2}<2-\frac{k^2+1}{k(k+1)^2}\\ \\ LHS<(2-\frac{1}{k})+\frac{1}{(k+1)^2}\\ LHS<2-\left(\frac{1}{k}-\frac{1}{(k+1)^2}\right)\\ LHS<2-\left(\frac{(k+1)^2}{k(k+1)^2}-\frac{k}{k(k+1)^2}\right)\\ LHS<2-\left(\frac{k^2+k+1}{k(k+1)^2}\right)\\ LHS<2-\frac{k^2+1}{k(k+1)^2}-\frac{k}{k(k+1)^2}\\ therefore\\ LHS<2-\frac{k^2+1}{k(k+1)^2}\\ LHS<2-\frac{1}{k+1}\\ \)
Therefore, if true for n=k then it must be true for n=k+1
Step 3
Since true for n=1, it must be true for n=2
Since true for n=2 it must be true for n=3, n=4,n=5, etc.
Therefore true for al n where \(n\in N\)
wow that must've took a while thanks so much! i needed this for my homework my teacher's not a forgiving person.