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The solution of the given equation is :
cosθ = 1/2 when θ = π/3 + 2kπ or 5π/3 + 2kπ
cosθ = -1 when θ = π + 2kπ
Since cos2θ + sin2θ = 1, sin2θ = 1 - cos2θ
So, the given equation is equivalent to 2(1 - cos2θ) - cosθ = 1
-2cos2θ - cosθ + 1 = 0
2cos2θ + cosθ - 1 = 0 (multiplying the entire equation by -1)
(2cosθ - 1)(cosθ + 1) = 0 (taking common)
cosθ = 1/2 or cosθ = -1 (on equating it to zero)
cosθ = 1/2 when θ = π/3 + 2kπ or 5π/3 + 2kπ
cosθ = -1 when θ = π + 2kπ
For more information about trigonometric ratios, visit
brainly.com/question/24496175
Answer:
B) (-10, -6) and (8, -6)
Step-by-step explanation:
Yea they are i would type more but here
18 kg of 15% copper and 72 kg of 60% copper should be combined by the metalworker to create 90 kg of 51% copper alloy.
<u>Step-by-step explanation:</u>
Let x = kg of 15% copper alloy
Let y = kg of 60% copper alloy
Since we need to create 90 kg of alloy we know:
x + y = 90
51% of 90 kg = 45.9 kg of copper
So we're interested in creating 45.9 kg of copper
We need some amount of 15% copper and some amount of 60% copper to create 45.9 kg of copper:
0.15x + 0.60y = 45.9
but
x + y = 90
x= 90 - y
substituting that value in for x
0.15(90 - y) + 0.60y = 45.9
13.5 - 0.15y + 0.60y = 45.9
0.45y = 32.4
y = 72
Substituting this y value to solve for x gives:
x + y = 90
x= 90-72
x=18
Therefore, in order to create 90kg of 51% alloy, we'd need 18 kg of 15% copper and 72 kg of 60% copper.
