Short Questions (Question 1 – 4)


Question 1:
Differentiate the expression 2x (4x2 + 2x – 5) with respect to x.

Solution:
2x (4x2 + 2x – 5) = 8x3 + 4x2– 10x
d d x (8x3 + 4x2 – 10x)
= 24x + 8x –10 



Question 2:
Given that  y = x 3 + 2 x 2 + 1 3 x ,  find  d y d x . .

Solution:
y = x 3 + 2 x 2 + 1 3 x y = x 3 3 x + 2 x 2 3 x + 1 3 x y = x 2 3 + 2 x 3 + 1 3 x 1 d y d x = 2 x 3 + 2 3 1 3 x 2 d y d x = 2 x 3 + 2 3 1 3 x 2



Question 3:
Given that  y = 3 5 x + 1 ,  find  d y d x

Solution:
y = 3 5 x + 1 = 3 ( 5 x + 1 ) 1 2 d y d x = 1 2 .3 ( 5 x + 1 ) 3 2 ( 5 ) d y d x = 15 2 [ ( 5 x + 1 ) 3 ] 1 2 d y d x = 15 2 ( 5 x + 1 ) 3



Question 4:
Given that  y = 3 5 u 5 , where u = 4+ 1. Find d y d x in terms of x.

Solution:
y = 3 5 u 5 ,   u = 4 x + 1 y = 3 5 ( 4 x + 1 ) 5 d y d x = 5. 3 5 ( 4 x + 1 ) 4 .4 d y d x = 12 ( 4 x + 1 ) 4