If 14 g of a radioactive substance are present initially and 7 yr later only 7 g remain, how much of the substance will be present after 17 yr?

2.60 gr

Step-by-step explanation:

We need to consider the function where Po is the initial substance k is the rate of decay and t is the time

We know that and at the 7 th year P(t) is 7

This means

We solve for k

y = 2x

step-by-step explanation:

if you divide each number in the sequence, you'll see that they all have a multiple factor of 2. each number in the series, and any other numbers which may continue, will be multiplied by 2. therefore, y is the next number in the sequence, and x is the current one, so, our formula will be y = 2x.

sina-sinb

cosb+cosa

tana-tanb

cos0+cos x pi/3

20tan

step-by-step explanation: