when i have to find rate of change of decrease in any value my ans comes in negative why??????????

Hemanshu,

The derivative measures the rate of change. The sign of the derivative indicates whether the function is increasing or decreasing. If the derivative is negative at some point on the curve then the function is decreasing at this point.

I hope this helps,
Penny

Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.