Question

For what value of k, the function f(x) = kx^2 + (2k^2-81)/2×(-x-12) is maximum at x = 9/4
a) 9/2
b) -9
c) -9/2
d) 9​

Answer 1

Answer:

c.d.f. of the continuous variable is given by,

f(x)=∫

−1

x

3

y

2

dy

=[

9

y

3

]

−1

x

=

9

(x

3

+1)

,x∈R

Consider P(x<1)=f(1)=

9

(1)

3

+1

=

9

2

P(x≤−2)=0

P(x>0)=1−P(x≤0)

=1−f(0)

=1−(

9

1

)=

9

8

P(1<x<2)=f(2)−f(1)

=1−

9

2

=

9

7