0 votes
in Sets, relations and functions by (90.1k points)
edited by
Let \(f:[1,3] \rightarrow R\) be a continuous function that is differentiable in \((1,3)\) an \(f^{\prime}(x)=|f(x)|^{2}+4\) for all \(x \in(1,3)\). Then,
(A) \(f(3)-f(1)=5\) is true
(B) \(f(3)-f(1)=5\) is false
(C) \(f(3)-f(1)=7\) is false
(D) \(f(3)-f(1)<0\) only at one point of \((1,3)\)

3 Answers

0 votes
by (90.1k points)
Ans : \((B, C)^{*}\)
Hint : By applying LMVT, there exist at least one \(c \in(1,3)\) such that \(\frac{f(3)-f(1)}{3-1}=f^{\prime}(c)\)
$$
\Rightarrow \mathrm{f}(3)-\mathrm{f}(1)=2 \cdot|\mathrm{f}(\mathrm{c})|^{2}+8 \Rightarrow \mathrm{f}(3)-\mathrm{f}(1) \geq 8
$$
0 votes
by
cialis next day delivery <a href="https://ordergnonline.com/">order cialis sale</a> medicine for erectile
0 votes
by
order cialis 10mg for sale <a href="https://ordergnonline.com/">tadalafil 20mg oral</a> pills for erection
...