Given f x 2x3 nbsp 9x2 nbsp 12x 1 nbsp find the intervals in which function is increasing and decrea......

Given ,f(x)= - 2x³  -9x²  -12x +1  ,find the intervals in which function is increasing and decreasing?

D f(x)/dx  = -6x²    -18x  -12

At dfx/dx  =0

X² +3x +2 =0

(x+2)(x+1)=0

X=-2  ,x=-1

X ? (-2  ,-1)

[-∞,-2] 

By: bhavesh kumar singh