If `H_(1),H_(2),H_(3),...,H_(2n+1)` are in H.P.,then `sum_(i=1)^(2n)(-1)'((H_(i)+H_(i+1))/(H_(i)-H_(i+1)))` is equal to`

If A_(1),A_(2) are between two numbers, then (A_(1)+A_(2))/(H_(1)+H_(2)) is equal to

IF a_(1),a_(2),a_(3),"...."a_(10) be in AP and h_(1),h_(2),h_(3),"...."h_(10) be in HP. If a_(1)=h_(1)=2 and a_(10)=h_(10)=3 , then find value of a_(4)h_(7) .

If H_1.,H_2,…,H_20 are 20 harmonic means between 2 and 3, then (H_1+2)/(H_1-2)+(H_20+3)/(H_20-3)=

If H_1, H_2, ,H_(20) are 20 harmonic means between 2 and 3, then (H_1+2)/(H_1-2)+(H_(20)+3)/(H_(20)-3)= a. 20 b.21 c. 40 d. 38

If 2, h_(1), h_(2),………,h_(20)6 are in harmonic progression and 2, a_(1),a_(2),……..,a_(20), 6 are in arithmetic progression, then the value of a_(3)h_(18) is equal to

underline(I_(2))O_(5)+H_(2)O to HIO_(3)

If H_1. H_2...., H_n are n harmonic means between a and b (!=a) , then the value of (H_1+a)/(H_1-a)+(H_n+b)/(H_n-b) =

A : When C_(2) H_(5) - O- CH_(3) is reacted with one mole of Hl then C_(2)H_(5)OH & CH_(3) I is formed . R : It is S_(N)1 reaction

Let A_(1), A_(2), A_(3), A_(4) be the areas of the triangular faces of a tetrahedron, and h_(1), h_(2), h_(3), h_(4) be the corresponding altitudes of the tetrahedron. If the volume of tetrahedron is 1//6 cubic units, then find the minimum value of (A_(1) +A_(2) + A_(3) + A_(4))(h_(1)+ h_(2)+h_(3)+h_(4)) (in cubic units).

If A_1,A_2,G_1,G_2 and H_1,H_2 are AM’s, GM’s and HM’s between two numbers, then (A_1+A_2)/(H_1+H_2). (H_1H_2)/(G_1G_2) equals _____