We know that sin2x=2sinxcosx
(search the net for proof if you wish)
So the original equation becomes
2sinxcosx-sinx=0
The two terms both have sinx that can be taken out to get:
sinx(2cosx-1)=0
This is true if sinx=0 or 2cosx-1=0 , rewritten: cosx=1/2
sinx=0 than x=2kπ
cosx=1/2 than x=π/3+2kπ
where k is an integer
Answer:
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Step-by-step explanation:
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The correct answer is: [C]: " -5 ΙxΙ = 25 " .
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In this answer choice, when you divide each side by "-5" ;
you get: " ΙxΙ = -5 ;
If x = 5, the result is "5" ; NOT "-5" .
If x = -5, the result is "5" ; NOT "-5" .
The "absolute value" of a value is always "zero" or greater.
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Answer choice: [C]: has no solution.
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Answer:
Adult tickets =125
Child tickets = 128
Step-by-step explanation:
Let the number of adult and children tickets sold be x and y respectively
So that
x+y= 253--------1
Since total sales/receipt is $2,771
And given that tickets for a dance recital cost $15 for adults and $7 for children hence
15x+7y= 2771-------2
Solving equation 1 and 2 simultaneously we have
x+y= 253---------------1
15x+7y= 2771----------2
Let us multiply equation 1 by 15 to get equation 3 to eliminate x and subtract equation 2 from 3
15x+15y=3795---------3
-{15x+7y= 2771----------2
0+8y=1024
8y= 1024
y= 1024/8
y= 128 tickets
So solve for x let us put y= 128 in equation 1
x+ 128=253
x=253-128
x= 125 tickets
