Question
Question: Let f(x) = \(\int_{–1}^{x}e^{t^{2}}\)dt and h(x) = f(1 + g(x)), where g(x) is defined for all x, g'(...
Let f(x) = ∫–1xet2dt and h(x) = f(1 + g(x)), where g(x) is defined for all x, g'(x) exists for all x, and g(x) ≤ 0 for x > 0. If h'(1) = e, g'(1) = 1 then the possible values which g(1) can take –
A
0
B
– 1
C
2
D
– 4
Answer
0
Explanation
Solution
Given f(x) = ∫–1xet2dt; h(x) = f(1 + g(x));
g (x) ≤ 0 for x > 0 Now, h(x) = ∫–11+g(x)et2 dt
On differentiating wrt x, we get
h'(x) = e(1+g(x))2 . g'(x)
h'(1) = e (given)
e(1+g(x))2 . g'(1) = e
∴ (1 + g(1))2 = 1
1 + g(1) = ± 1 ⇒ g(1) = 0 or g(1) = – 2.