Question

show that the progression 3,7,11,15,..... is an ap. write down its first term and common difference

Answer 1

First term of any series is its first number which is 3 here,

So, if it is an AP , first term is 3

Proof : if it is an AP , difference of any term and its previous term will be same always and this is also known as common difference as it is common in all terms,

Difference between second and first term,

=> 7 - 3

=> 4   ---------  ( 1 )

Difference between third and second term,

=> 11 - 7

=> 4       --------- ( 2 )

Difference between the fourth and third term,

=> 15 - 11

=> 4    ----------( 3 )

As the difference( 4 ) is same ,  progression 3,7,11,15,..... is an AP.