Which function represents exponential decay?

the last, since exponential function with base between 0 and 1

Step-by-step explanation:

Exponential equation is in the form of

'a' represents the initial amount

'b' represents the growth or decay factor

when the value of b is between 0 and 1 then it is decay function

In the function

the value of b is that is less than 1

So the function represents a exponential decay.

not only in mathematics, scientific proof also are required in the other field of science. also maths proofs are of particular structure, containing steps and logics. so proving is like doing science, it is science. that's why it is important to prove. 

an inaccurate proof leads to errors, or stating results that are not accurate.  which wil mess the probelm up you dont want this