AP and GP

Question 1

nth term of AP

Answer 1

aₙ = a+(n-1)d

Question 1

first term of AP

Answer 1

a₁ = a

Question 2

first term of GP

Answer 2

a₁ = a

Question 3

nth term of GP

Answer 3

aₙ = arⁿ⁻¹

Question 4

Sum of AP

Answer 4

Sₙ = n * average = n*(last term + first term)/2)
= n/2 * ( 2a+(n-1)d)

Question 5

Sum of GP

Answer 5

Question 6

AP (explanation)

Answer 6

Question 7

GP (explanation)

Answer 7

Question 8

1+2x+3x²+4x³+……… ?

Answer 8

(1-x)⁻² [(1-x) raise to the power -2 emphasise on negative]