2cosx=2sin2x. Sin2x is an identity for 2sinxcos. So 2[2sinxcosx] gives you 4sinxcosx. 2cosx=4sinxcosx. Divide 2cosx on both sides and gives you 2sinx=0 and divide again, sinx=0. Sinx is 0 at 0 and 360 degrees, or pi and 2pi. So thats what x would be. 0,360,pi,2pi.
Answer:
Juan wins the race
Step-by-step explanation:
<u>The graph is shown in attached image.</u>
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The black line is Juan's graph.
The green line is Antonio's graph.
The graph shows the distance (y-axis) with time (x-axis).
The end of the curve(s) means the end of the race. Both curve's ending point in y-axis is 4 miles so the end of the race is 4 miles.
But in x-axis, we see the time:
Juan finishes at 13 minutes
Antonio finishes at 15 minutes
<u>Definitely Juan wins the race</u>
Answer:
144
Step-by-step explanation:
Answer:
4 brothers and 3 sisters
Step-by-step explanation:
Let x be the number of brothers and y be the number of sisters in the family.
1. Each brother has x-1 brothers and y sisters. If each brother has as many sisters as brothers, then

2. Each sister has y-1 sisters and x brothers. If each sister has twice as many brothers as she has sisters, then

3. Solve the system of two equations:

Then
