Answer:
When proving identities, the answer is in the explanation.
Step-by-step explanation:
I have two terms in this denominator here.
I also know that 
by Pythagorean Identity.
So I don't know how comfortable you are with multiplying this denominator's conjugate on top and bottom here but that is exactly what I would do here. There will be other problems will you have to do this.
Big note here: When multiplying conjugates all you have to do is multiply fist and last. You do not need to do the whole foil. That is when you are multiplying something like 
, the result is just 
.
Let's do that here with our problem in the denominator.
In that last step, I apply the Pythagorean Identity I mentioned way above.
Now You have a factor of cos(y) on top and bottom, so you can cancel them out. What we are really saying is that cos(y)/cos(y)=1.
This is the desired result.
We are done.
72 I think I hope its right I had to write all over my paper lol
Here speed of first train is slower than speed of second train. So if they catch up , the distance traveled will be same since they left the same station at different times.
But the time traveled will be different .
Let us say the two trains meet at time t ,
Distance = speed * time
Distance traveled by first train = 40 t
Since second train is leaving after three hours , so
Distance traveled by second train = 60(t-3)
As discussed earlier, distance traveled will be same, so
distributing 60 over t-3
t=9
So the second train will meet the first at 9 p.m.
Step-by-step explanation:
A compound contains atoms of different elements chemically combined together in a fixed ratio. An element is a pure chemical substance made of same type of atom. ... Compounds contain different elements in a fixed ratio arranged in a defined manner through chemical bonds. They contain only one type of molecule.
