Question

5 marks question long answer type

dont spam ​

Answer 1

Let the same common difference of two AP's is d. Given that, the first term of first AP and second AP are 2 and 7 respectively, then the AP's are

2,2+d,2+2d,2+3d......

and 7,7+d,7+2d,7+3d......

Now, 10th terms of first and the second AP are 2+9d and 7+9d, respectively

So, their difference is 7+9d-(2+9d)=5

Also, 21st terms of first and second AP are 2+20d-(2+9d)=5

Also, if the an and b are the nth terms of first and second AP.

Then, bn-an=[7+(n-1)d]-[2+(n-1)d]=5

Hence, the difference between any two corresponding terms of such AP's is the same as the difference between their first terms.

Answer 2

Let the same common difference of two AP's is d.

Giventhat,

the first term of first AP and second AP are 2 and 7 respectively, then the AP's are

2,2+d,2+2d,2+3d......

and 7,7+d,7+2d,7+3d......

Now,10th terms of first and the second AP are 2+9 d and 7+9 d,respectively

So,their difference is7+9d-(2+9d)=5

Also,21st terms of first and second AP are2+20d-(2+9d)=5

Also,if the an and b are thenth terms of first and second AP.

Then,bn-an=[7+(n-1)d]-[2+(n-1)d]=5

Hence,the difference between any two corresponding terms of such AP's is the same as the difference between their first terms.