Answer:
c
Step-by-step explanation:
1 + tan²theta = sec²theta
tan²theta = 3² - 1
tan²theta = 8
tan theta = sqrt(8)
Positive because Quadrant 1
sqrt(8) = sqrt(4×2) = sqrt(4)×sqrt(2)
= 2×sqrt(2)
We have been given that the standard deviation of a group of 20 scores is 15 and we are asked to find variance.
Since we know variance is square of standard deviation. In order to find out the variance of the given data we have to take the square of 15.

Therefore, our variance is 225.
The first one is the answer you're looking for
Answer:

Step-by-step explanation:
The half life is the amount of time it takes a substance to decay to half of its original amount.
Since the radioactive substance has a half life of 1000 years, there will be half of it left after 1000 years.
So, the fraction that will be left after 1000 years is 
Answer:
гафу итегез, мин ярдәм итә алмыйм, миңа бик кирәк
Step-by-step explanation:
гафу итегез, мин ярдәм итә алмыйм