To evaluate tanα, we first simplify the general term of the given summation.
The given equation is:
α=4π+∑p=111tan−1(1+22p−12p−1)
Let Tp denote the p-th term of the summation:
Tp=tan−1(1+22p−12p−1)
Notice that 22p−1=2p⋅2p−1 and 2p−1=2p−2p−1. We can rewrite Tp as:
Tp=tan−1(1+2p⋅2p−12p−2p−1)
Using the standard inverse trigonometric identity:
tan−1(1+xyx−y)=tan−1x−tan−1yfor x,y>0
we get:
Tp=tan−1(2p)−tan−1(2p−1)
Now, summing Tp from p=1 to 11 forms a telescoping series:
∑p=111Tp=∑p=111[tan−1(2p)−tan−1(2p−1)]
Expanding the sum:
∑p=111Tp=(tan−1(21)−tan−1(20))+(tan−1(22)−tan−1(21))+⋯+(tan−1(211)−tan−1(210))
All intermediate terms cancel out, leaving:
∑p=111Tp=tan−1(211)−tan−1(20)
Since 20=1 and tan−1(1)=4π:
∑p=111Tp=tan−1(211)−4π
Substitute this result back into the expression for α:
α=4π+(tan−1(211)−4π)
α=tan−1(211)
Taking the tangent on both sides:
tanα=tan(tan−1(211))=211
Since 211=2048:
tanα=2048