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For how many values of x in the interval 2n<x<5n is cos(2x)=1/2?
A. 6
B. 3
C. 10
D. 1
E. 0
This is one of my college pre cal homework problems and i cant figure it out. This class just moves so fast during the summer. Could you please explain how you got it also! Thanks
2 Answers
- Anonymous10 years agoFavorite Answer
its (A)
first of all it says 2n<x<5n
and it says 2x=1/2
now we need to make the "x" into "2x" in (2n<x<5n)
how? you multiply by 2 on every number.
2(2n)<2(x)<2(5n)
4n<2x<10n
the only number that you gave me between 4-10 is 6
im not sure what was your question but i hope its right.
Source(s): King Fez and i just got out of senior high school - Anonymous10 years ago
The simplest method would be to look at the graph of (cos2x) along the interval of two pi to five pi and visually count the number of times the equation has a value corresponding to 1/2.