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Question
Write the expression of the common difference of an A.P. whose first term is a and nth term is b.
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Solution
Here, we are given
First term = a
Last term = b
Let us take the common difference as d
Now, we know
an = a + (n-1)d
So,
For the last term (an),
b = a + (n-1) d
b - a = (n-1) d
` d = (b-a)/(n-1)`
Therefore, common difference of the A.P. is ` d = (b-a)/(n-1)`
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