If y= -1 ( 3 x-4 x4 x+3 x )+2 -1 ( x1+ 1-x2 ), then dydx at x= 32 is equal to :
- 3
- -1
- 1
- 2
Answer
(3) 1
Solution
First term: 3 x-4 x4 x+3 x= 34- x1+ 34 x= ( -x), where = 34
Near x= 32, -x (- 2, 2 ), so -1 ( -x)= -x; derivative =-1
Second term: put x= , [- 2, 2 ]: 1+ = 2
2 -1 ( 2 )= = -1x; derivative = 1 1-x2
dydx=-1+ 1 1-x2
At x= 32: 1- 34= 12 dydx=-1+2=1
Answer: (3)