We will use double angle identities:
cos (5x ) = sin (10x )
cos (5x ) = 2 cos (5x ) sin ( 5x )
cos ( 5 x) - 2 cos ( 5 x ) sin ( 5x ) = 0
cos ( 5 x ) · [ 1 - 2 sin (5 x) ] = 0
cos ( 5 x ) = 0 or : 1 - 2 sin (5 x) = 0
5 x = π/2 +kπ, k∈Z sin (5 x) = 1/2
x1 = π/10 + kπ/5 5 x = π/6+2kπ , k∈ Z
5 x = 5π/6 +2kπ , k∈ Z
x 2 = π/30 +2kπ/5
x 3 = π/9 + 2kπ/5
1 gallon cost $15
1 quarts cost $4
1 quarts = 1/4 gallon
15x for number of gallon cans
2 cans at $4 each = $8
15x + 8 = 53
Subtract 8 from both sides:
15x = 53-8
15x = 45
Divide both sides by 15:
x = 45/15
x = 3
She bought 3 gallon cans of paint
Plus she bought 2 quart cans, which is equal to a half gallon.
She bought a total of 3.5 gallons of paint.
Step-by-step explanation:
you need too look somewhere else
Your answer is c
Hope this helps :)
Answer:
Step-by-step explanation:
A) x/840=1/21
x=(1/21)*840=840/21=40
x=40
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B) 14/x=16/20
simplify 16/20 into 4/5
14/x=4/5
x=14/(4/5)=(14/1)(5/4)=70/4
simplify
x=35/2