Answer:
15 possible combinations
Step-by-step explanation:
Given


Required
Determine the possible number of combinations
The question emphasizes on "selection" which means "combination".
So; To answer this question, we apply the following combination formula:

In this case:


The formula becomes:






<em>Hence, there are 15 possible combinations</em>
Answer:
Selena's annual intake home salary is $ 26,640.
Step-by-step explanation:
Since Selena's gross annual salary as the content editor of a fashion Magazine is $ 40,000, and she contributes 10% of her salary before she pays taxes to a retirement account, and 25% of her remaining salary is then consumed in state and federal taxes, To determine what is Selena's annual intake home salary if she also has to pay $ 30 for health Insurance each month, the following calculation must be performed:
40,000 - (40,000 x 0.1) - (40,000 x 0.9 x 0.25) - (30 x 12) = X
40,000 - 4,000 - 9,000 - 360 = X
26.640 = X
Therefore, Selena's annual intake home salary is $ 26,640.
Sin2(x) +cos(x)=1
from the relation: (sin2(x) +cos2(x) =1 )
so , sin2(x)=1-cos2(x)
by subs. in the main eqn.
1-cos2(x) + cos(x) =1
by simplify the eqn.
cos(x) -cos2(x)=0
take cos(x) as a common factor
cos(x)* (1-cos(x))=0
then cos(x)=0 && cos(x)=1
cos(x)=0 if x= pi/2
& cos(x) = 1 if x = 0 , 2*pi
so the solution is x= {0,pi/2 , 2*pi}