Answer:
Step-by-step explanation:
given the expression;
cos(2x) = cos(x)
According to trig identity;
cos(2x) = cos(x+x)
cos(2x) = cos x cos x - sinx sinx
cos(2x) = cos²(x)-sin²(x)
cos(2x) = cos²(x)-(1-cos²x)
cos(2x) = cos²(x)+cos²x-1
cos(2x) = 2cos²(x)-1
2cos²(x)-1 = cos(x)
let P = cosx
2P²-1 = P
2P²-P-1 = 0
Factorize;
2P²-2P+P-1 = 0
2P(P-1)+1(P-1) = 0
2P - 1 = 0 and P-1 = 0
P = 1/2 and 1
cosx = 1/2 and cos x = 1
x = arccos 1/2
x = π/3
Also;
x = arccos1
x = 0
Hence the value of x are 0 and π/3
Also the angle = π+ π/3 = 4π/3
The angles are 0, π/3 and 4π/3
Answer:
X=10
MArk me brainliest
Step-by-step explanation:
<h3>
Answer: m = 25</h3>
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Work Shown:
Triangle ABC is congruent to triangle DEF. The order of the lettering is important because it tells us how the angles pair up. We see that angle B and angle E are the second letters of ABC and DEF respectively. Because the triangles are congruent, this leads to angle B = angle E.
Angle B is shown to be 20 degrees, so,
angle E = angle B
2(m-15) = 20
m-15 = 20/2
m-15 = 10
m = 10+15
m = 25
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A slightly alternative way to solve:
2(m-15) = 20
2m-30 = 20
2m = 20+30
2m = 50
m = 50/2
m = 25
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Checking the answer:
2(m-15) = 20
2(25-15) = 20
2(10) = 20
20 = 20
We get the same thing on both sides, so we end up with a true equation. This means the first equation is true when m = 25. The solution has been confirmed.
15y + 31 = 61
15y = 61 - 31
15y = 30
y = 30 ÷ 15
<u>y = 2</u>