If a1,a2,a3,…. an are in AP with common difference 5 and if aiaj≠-1fori,j=1,2,….N, then tan-15[1+a1a2]+tan-15[1+a2a3]+….+tan-15[1+an-1an]=
tan-15[1+an-1an]
tan-15a1[1+ana1]
tan-15n-5[1+ana1]
tan-15n-5[1+an+1a1]
tan-15n[1+ana1]
Explanation for the correct option:
Finding the value of tan-15[1+a1a2]+tan-15[1+a2a3]+….+tan-15[1+an-1an]:
Given a1,a2,a3,….are in AP with common difference d=5
a2-a1=a3-a2=a4-a3=.....=an-an-1=5tan-15[1+a1a2]+tan-15[1+a2a3]+….+tan-15[1+an-1an]=tan-1(a2-a1)[1+a1a2]+tan-1(a3-a2)[1+a2a3]+….+tan-1(an-an-1)[1+an-1an]=tan-1a2-tan-1a1+tan-1a3-tan-1a2+....tan-1an-tan-1an-1=tan-1an-tan-1a1=tan-1(an-a1)[1+a1an]=tan-1(an-an-1)[1+an-1an]=tan-15(n-1)[1+an-1an]=tan-1(5n-5)[1+an-1an]
Hence, the correct option is (C).
If a1,a2,a3.....an are in A.P. Where ai>0 for all i, then the value of 1√a1+√a2+1√a2+√a3+.........+1√an−1+√an=