Definite Integration Question 106
Question: $ ( \int _{0}^{a}{xdx} )\le (a+4), $ then
[RPET 2000]
Options:
A) $ \frac{24}{5}\pi $
B) $ -2\le a\le 4 $
C) $ -2\le a\le 0 $
D) $ a\le -2ora\ge 4 $
Show Answer
Answer:
Correct Answer: B
Solution:
$ \int_0^{a}{xdx\le a+4} $
$ \Rightarrow \frac{a^{2}}{2}\le a+4 $
$ \Rightarrow a^{2}\le 2a+8 $
$ \Rightarrow a^{2}-2a-8\le 0 $
$ \Rightarrow (a-4)(a+2)\le 0 $
$ \Rightarrow -2\le a\le 4 $ .
BETA
