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How to find the general term formula of the mixed sequence of equal difference and equal ratio?
Sum of arithmetic sequence: (first term + last term) x tolerance divided by 2 arithmetic sequence general term: which term = first term + (number of terms - 1) x tolerance arithmetic sequence example: original problem: in an arithmetic sequence {an}, a1 + A4 = 133, A2 + a3 = 70, find the general term formula of this sequence. A1 + A4 = A1 (1 + Q ^ 3) = 133, A2 + a3 = A1 (Q + Q ^ 2) =
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- 7. 1: In △ ABC, let Tana / tanb = 2C-B / B, find the value of a? 2: in △ ABC, a + B = 10, COSC is a root of the square of equation 2x - 3x-2 = 0, find the minimum value of perimeter of △ ABC?
- 8. Evaluation: sin50 degrees (1 + root 3 times tan10 degrees) Please write down the process of simplification
- 9. In △ ABC, we know that a ＞ B ＞ C, and a = 2c, the opposite sides of a, B, C are a, B, C respectively, and a, B, C form an arithmetic sequence, and B = 4, so we can find the length of a, C It's before 20 o'clock today,
- 10. In △ ABC, let a + C = 2B, a-c = π 3, find the value of SINB
- 11. Find out the triangle and circle. The number represented by the square? Triangle + square + circle = 40, triangle + circle + square + square = 46, triangle + circle
- 12. Triangle plus square is equal to 240, a triangle is equal to three square, ask triangle more than ten, square more than ten?
- 13. Triangle + square = 35, triangle + circle = 52, square + circle =?
- 14. 2 circle + triangle + box = 66 2 triangle + box + circle = 62 2 Box + circle + triangle = 64 circle = () triangle = () box = ()
- 15. Box = circle + triangle, triangle = 2 circle, if triangle = 4, then box = () How do you do it?
- 16. 1 triangle + square + circle = 23 kg, 2 square + 2 circle = 22 kg, 2 triangle + 1 circle = 28 kg. What is the weight of triangle, circle and square?
- 17. Circle plus triangle = 43 circle plus square = 37 triangle + square = 40 circle plus square
- 18. Circle plus positive equals 72, three plus positive equals 58, triangle plus circle equals 43, what is triangle equal to, circle equal to, positive equal to
- 19. Triangle 1 + triangle 2 = 11 circle 1 + circle 2 = 22 positive 1 + positive 2 = 33 triangle 1 + circle 2 = 12 positive 1 + triangle 2 = 31 then positive 1 + three 2 =?
- 20. Circle plus triangle = 43 circle plus square = 37 triangle + square = 40 circle, triangle, square