Question

qn below

Answer 1

answer is D

Answer 2

do u know why?

Answer 3

Well thats the answer I marked on my exam last week .

Answer 4

I just observed that there is a point of inflexion

Answer 5

\[\int\limits_{}f'(x)\ge4.2x\]

Answer 6

so, f(x)=>4.2x+C

Answer 7

substituting f(1)=-2 with this

Answer 8

makes C<=-6.2

Answer 9

then ?

Answer 10

then we put it in 1<=x<=6

Answer 11

as C must be under -6.2 it's negative, and by the formula 4.2x-C

Answer 12

it will make it positive till infinity

Answer 13

I see

Answer 14

and the only approach is -6.2 to be 0

Answer 15

great my answer is correct :)

Answer 16

It was an exam similar to SAT each question counts .Thanks for helping me review :)

Answer 17

fine :D