NCERT Class XI Mathematics - Limits and Derivatives - Solutions
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Question : 23
Total: 72
Find
f (x) and
f (x), where
f (x) ={
f (x) =
Solution:
We have, f (x) = {
For
f (x) , we have to evaluate
f (x) and
f (x) separately as f(x) is defined differently on left and right of 0.
Now,
f (x) =
(2x + 3) = 2 . (0) + 3 = 3
and
f (x) =
3 (x + 1) = 3 (0 + 1) = 3.
Thus we see,
f (x) =
f (x) = 3
∴
f (x) = 3
Now,
f (x) 3 (x + 1) = 3 × 2 = 6
∴
f (x) = 6 and
f (x) = 3.
For
Now,
and
Thus we see,
∴
Now,
∴
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