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It is known that the opposite sides of the three inner angles a, B and C of △ ABC are a, B and C respectively. If a, B and C form an arithmetic sequence and 2cos2b-8cosb + 5 = 0, the size of angle B is calculated and the shape of △ ABC is judged
From 2cos2b-8cosb + 5 = 0, we can get 4cos2b-8cosb + 3 = 0, that is, (2cosb-1) (2cosb-3) = 0. The solution is CoSb = 12 or CoSb = 32 (rounding off). ∵ 0 ＜ B ＜ π, ∵ B = π 3 and ∵ a, B, C form an arithmetic sequence, that is, a + C = 2B. ∵ CoSb = A2 + C2 − b22ac = A2 + C2 − (a + C2) 22ac = 12. The simplification is A2 + c2-2ac = 0, the solution is a = C, ∵ B = π 3 ∵ ABC is an equilateral triangle
It is known that the opposite sides of the three inner angles a, B and C of △ ABC are a, B and C respectively. If a, B and C form an arithmetic sequence and 2cos2b-8cosb + 5 = 0, the size of angle B is calculated and the shape of △ ABC is judged
From 2cos2b-8cosb + 5 = 0, we can get 4cos2b-8cosb + 3 = 0, that is, (2cosb-1) (2cosb-3) = 0. The solution is CoSb = 12 or CoSb = 32 (rounding off). ∵ 0 ＜ B ＜ π, ∵ B = π 3 and ∵ a, B, C form an arithmetic sequence, that is, a + C = 2B. ∵ CoSb = A2 + C2 − b22ac = A2 + C2 − (a + C2) 22ac = 12. The simplification is A2 + c2-2ac = 0, the solution is a = C, ∵ B = π 3 ∵ ABC is an equilateral triangle
It is known that the opposite sides of the three inner angles a, B and C of △ ABC are a, B and C respectively. If a, B and C form an arithmetic sequence and 2cos2b-8cosb + 5 = 0, the size of angle B is calculated and the shape of △ ABC is judged
From 2cos2b-8cosb + 5 = 0, we can get 4cos2b-8cosb + 3 = 0, that is, (2cosb-1) (2cosb-3) = 0. The solution is CoSb = 12 or CoSb = 32 (rounding off). ∵ 0 ＜ B ＜ π, ∵ B = π 3 and ∵ a, B, C form an arithmetic sequence, that is, a + C = 2B. ∵ CoSb = A2 + C2 − b22ac = A2 + C2 − (a + C2) 22ac = 12. The simplification is A2 + c2-2ac = 0, the solution is a = C, ∵ B = π 3 ∵ ABC is an equilateral triangle
It is known that the opposite sides of the three inner angles a, B and C of △ ABC are a, B and C respectively. If a, B and C form an arithmetic sequence and 2cos2b-8cosb + 5 = 0, the size of angle B is calculated and the shape of △ ABC is judged
From 2cos2b-8cosb + 5 = 0, we can get 4cos2b-8cosb + 3 = 0, that is, (2cosb-1) (2cosb-3) = 0. The solution is CoSb = 12 or CoSb = 32 (rounding off). ∵ 0 ＜ B ＜ π, ∵ B = π 3 and ∵ a, B, C form an arithmetic sequence, that is, a + C = 2B. ∵ CoSb = A2 + C2 − b22ac = A2 + C2 − (a + C2) 22ac = 12. The simplification is A2 + c2-2ac = 0, the solution is a = C, ∵ B = π 3 ∵ ABC is an equilateral triangle
RELATED INFORMATIONS
- 1. It is known that a, B and C are the opposite sides of the three internal angles a, B and C of △ ABC, and a, B and C form an arithmetic sequence, B = 60 °, then the shape of △ ABC is______ ．
- 2. Given that a > 0 and a is not equal to 1, f (x) = x ^ 2-A ^ x, when x belongs to (- 1,1), all f (x)
- 3. Given the function f (x) = log a ^ (x ^ 2-2x + 3) (a is greater than 0, a is not 1), when a belongs to [0,3], f (x) is greater than - 1, find the value range of real number a A is the base. Find the value range of A
- 4. If loga (1 / 3) 0, a ≠ 1), then the value range of real number a is________ . Another small question is whether 3 ^ 2 is greater than or less than x if log3x is less than 2
- 5. The inequality | x + 1x | > | a − 5 | + 1 holds for all non-zero real numbers x, then the value range of real number a is______ ．
- 6. If three points a (3,1), B (- 2, K) and C (8.1) can form a triangle, the value range of real number k can be obtained
- 7. If the inequality | X-2 | - | x + 2 | ≥ a, then the value range of real number a is
- 8. a. If B, u are positive real numbers, and 1 / A + 9 / b = 1, then a + B ≥ u is constant
- 9. Let f (x, y) = x + Y-A (x + 2 * (2XY) ^ 0.5, where x and y are positive real numbers. If f (x, y) is greater than or equal to zero for any X and y, the range of a is obtained?
- 10. Formula and derivation of coordinates of parabola vertex
- 11. Y = √ loga ^ (x-1)
- 12. Given f (x) = loga (x + 1-A), find the set of values that make f (x) > 1
- 13. If a & # 178; > b > a > 1, compare log B B / A, log B a, log a B
- 14. A = log (3) π B = log (7) 6 C = log (2) 0.8 which is bigger,
- 15. If log3 (2) = A and 3 ^ B = 5, then a and B are used to denote that the root of log (3) is 30
- 16. 2. If x ∈ a = > x ∈ B, then the relation between a and B is 1. If loga 3 > logb 3 > 0, A.0
- 17. F is the focal point of the parabola y2 = 2x, m (3.2), P moves on the parabola, when PM + PF is the minimum, the coordinates of point P This is the content of elective 2-1 in senior two
- 18. Known: as shown in the figure, m (3,2), n (1, - 1). Point P makes PM + PN shortest on the y-axis, and calculates the coordinates of point P
- 19. How to write am and PM in the morning Do you want capitalization? Do you want a little bit in the middle? A.m or am, am, a.m?
- 20. Should I choose "am" or "PM" to set the alarm clock at 12 noon?