The fabric costs $8.95 per yard.
Answer:
3 sin(41t) - 3 sin(t)
Step-by-step explanation:
The general formula to convert the product of the form cos(a)sin(b) into sum is:
cos(a) sin(b) = 0.5 [ sin(a+b) - sin (a-b) ]
The given product is:
6 cos(21t) sin(20t) = 6 [ cos(21t) sin(20t) ]
Comparing the given product with general product mentioned above, we get:
a = 21t and b = 20t
Using these values in the formula we get:
6 cos(21t) sin(20t) = 6 x 0.5 [ sin(21t+20t) - sin(21t-20t)]
= 3 [sin(41t) - sin(t)]
= 3 sin(41t) - 3 sin(t)
Therefore, second option gives the correct answer
The speed of current will be "4.5 mph" and the rate Pratap can row in still water will be "8.5 mph".
What does "speed" mean in mathematics?
- Speed is what it means. the speed of a change in an object's location in any direction.
- Speed is defined as the ratio of distance to the amount of time it took to cover that distance.
- Speed is a scalar quantity because it just has a direction and no magnitude.
Given:
Distance "26 miles" in time "2 hours".
Let,
Speed of water = y
Pratap speed when rowing in still water = x
As we know,
Speed = distance/time
then,
x + y = 26/2
x + y = 13
x = 13 - y
In return trip took him time "6.5 hours",
x - y = 26/6.5
x - y = 4
By substituting the value of "x", we get
13 - y - y = 4
13 - 2y = 4
2y = 13 - 4
2y = 9
y = 9/4 = 4.5 mph (Rate of the current)
By substituting the value of "y", we get
x = 13 - a
x = 13 - 4. 5 = 8.5 mph (Pratap can row in still water)
Learn more about speed
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Since the sum of two numbers is 67
and one number is p
so the other number is (67-p)
Just do 4x5 then add the zeros