Use a half-angle identity to find the exact value of Sin/8 a. √2 + √2 √2+ √2 2 b. V2-E d. √2-√2 2<

Question

Use a half-angle identity to find the exact value of Sin/8
a.
√2 + √2
√2+ √2
2
b. V2-E
d. √2-√2
2
Please select the best answer from the choices provided

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Nguyệt Ánh 3 years 2021-08-06T04:18:18+00:00 1 Answers 4 views 0

Answers ( )

    0
    2021-08-06T04:20:00+00:00

    Answer:

    To solve this problem, we need to use the following two facts:

    1) If a quadratic equation has integer coefficients only, and if one of the roots is a + √b (where a and b are integers), then a – √b is also a root of the equation.

    2) If r and s are roots of a quadratic equation, then the equation is of the form x^2 – (r +s)x + rs = 0.

    Since we know that 1 – √2 is a root of the quadratic equation, we can let:

    r = 1 + √2

    and

    s = 1 – √2

    Thus, r + s = (1 + √2) + (1 – √2) = 2 and rs = (1 + √2)(1 – √2) = 1 – 2 = -1.

    Therefore, the quadratic equation must be x^2 – 2x – 1 = 0.

    Answer: D

    Step-by-step explanation:

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )