Answer:
12.56
Step-by-step explanation:
The formula for circumference is either πr² πd. Thats basically just multiplying. All you have to do is take the the diameter and multiply it times pi and you get the answer. In some cases they want you to use the radius; radius is diameter divided by 2. Example is if 4 is the diameter 2 is the radius. For this one i did 4 times 3.14(pi).
I hope that helps!
19.......................................
Use the double angle function sin2x = 2sinxcosx.
2sinxcosx + sinx = 0
For the first part of the problem, consider the solutions on the interval where sinx = 0
x = 0, pi
Now consider the solutions where sinx does NOT equal zero.
2sinxcosx + sinx = 0
2sinxcosx = - sinx
2cosx = - 1
cosx = - 1/2
x = 2pi/3, 4pi/3
Rebecca has 21 math problems
She has solved none....
2-7=-5
You cannot solve negative five problems
Answer: 0
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