Question

in an arithmetic series, fifth term is double of the third term. prove that thirteenth term is double of the seventh term

Answer 1

ι нσρє тнιѕ нєℓρѕ υн συт!!

Answer 2

Let the first term of the AP be a and common Difference be d

a₅=2a₃

[a+(5-1)d]=2[a+(3-1)d]

a+4d=2a+4d

a=0

♥ ♥ ♥

a₁₃=a+12d

a₁₃=0+(2×6d)

a₁₃=(0×2)+(6d×2)

a₁₃=2[0+6d]

a₁₃=2[0+(7-1)d]

a₁₃=2[a+(7-1)d]

a₁₃=2×a₇