Answer:
Identity is verified.
Step-by-step explanation:
We have to verify the identity 
To prove any identity we always prove one side(either left hand side or right hand side) of the equation equal to the other side.
In this identity we take the left hand side first

(as we know cos(a+b) = cosa×cosb-sina×sinb)


= - sinx ( Right hand side)
Hence identity is proved.
Answer:
The father is 50 and his son is 15.
Step-by-step explanation:
Double the tens digit of the father's age = 10
Plus 5 = 15 (the age of the son)
50 + 15 = 65 (the sum of their ages)
The reverse of the digits of the son's age is 51.
Subtract 1 = 50 (the age of the father)
Answer: After 7 years the number of birds of species A and B are same. and the number of birds during that year will be 140.
Step-by-step explanation:
Given: Sharon is conducting research on two species of birds at a bird sanctuary.
The number of birds of species A is represented by the equation below,where S represents the number of birds, x years after beginning her research.

The number of birds of species B is represented by the equation below,where S represents the number of birds, x years after beginning her research.

To plot the above function, first find points by which they are passing.
For species A, At x=0 , 
At x=2 , 
Similarly find more points and plot curve on graph.
For species A, At x=0 , 
At x=2 , 
Plot a line with the help of these two points.
Now, from the graph the intersection of curve (for A) and line (for B) is at (7,140) which tells that After 7 years the number of birds of species A and B are same. and the number of birds during that year will be 140.
Answer:
Radius of tire=0.58 meter
Step-by-step explanation:
as we know that the
Circumference of the tire=2*3.14*r
and it needs to rotate 30 times to cover the street distance of 360 feet
So, the below equation would be used to find the radius of tire in the meters
360/3.28084=30*2*3.14*r
r=0.5824203822 meters
Hence

Answer:
No
Step-by-step explanation: They are not because different banks have different interest rates on accounts, different fees and more