(1) The minimum value of y = 2cos square x + (root sign 3) sin2x + A in [0 degree, 90 degree] is - 4. Find the value of A (2) Prove cos20cos40cos80 = 1 / 8

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• 1. It is known that x = 3 is the solution of the linear equation 2x - (K / 2-1) x-3 = 0 with respect to x, and the value of K is obtained
• 2. It is known that one root of the linear equation x & # 178; + 2x + M = 0 with respect to X is x = - 3 to find the value of M and the other root of the equation
• 3. It is known that x = 1 is the value of M for the linear equation of one variable 2x-m + 1 = 0
• 4. If the solution of (2x-r / 3) - (x-3r / 2) = 1 is x = - 1, then the value of R is
• 5. 1 / 2x + {2 / 3x + 3 / 1y square], where x = negative 2 and y = 2 / 3
• 6. Solve the equation of one variable degree. (1) 2x + 5 = 3 (x-1) (2) 3x + 52 = 2x − 13 (3) x + 12 − 1 = 2 + 2 − X4
• 7. One variable linear equation exercise.. 1-x = - 2 (3x-1) - 1.3 / 2x-2 / 3 = 4 / 1x-4 / 3. (6x-5) + [2x - (4x-1)] = - 24
• 8. It is known that the absolute value + 7 = 0 of the equation (m-1) x m is a linear equation of one variable with respect to X. the value of M and the solution of the equation are obtained Help me
• 9. M is a known number, solve the binary linear equations composed of 7x + 3Y = 4 and 5x-y = M-1!
• 10. 5x > 7x solve the following inequality Solve the following inequality
• 11. Given that Y1 = 1 / 5x + 1, y2 = (2x + 1) / 4, when what is the value of X, Y1 and Y2 are opposite to each other?
• 12. Given that Y1 = 2x + 1, y2 = 5x-8, when what is the value of X, are Y1 and Y2 opposite to each other?
• 13. Let Y1 = 1 / 5x + 1, y2 = 2x + 1 / 4, when what is the value of X, Y1 and Y2 are opposite numbers?
• 14. Let Y1 = 1 / 5x + 1, y2 = (2x + 1) / 4, when what is the value of X, Y1 and Y2 are opposite numbers to each other? (solved by a linear equation of one variable)
• 15. Given that Y1 = 2x-1, y2 = 5x + 7, when x is what value, Y1 is smaller than Y2 by 1
• 16. It is known that the parabolic equation y = 4x square, the straight line L passes P (- 2,1), and the slope is K. when what is the value of K, there is only one common point between the straight line L and the parabola There are two common points, no common points? Ask for detailed explanation
• 17. It is known that the equation of parabola is y quadratic = 4x, the straight line I passes through the fixed point P (- 2.1), and the slope is K It is known that the equation of parabola is y quadratic = 4x, the straight line I passes through the fixed point P (- 2.1), and the slope is K. when the value of K is, the straight line and parabola have only one common point and two common points
• 18. It is known that the parabolic equation y ^ 2 = 4x, the straight line L passes through the fixed point P (- 2,1), and the slope is K. when k is the value, the straight line L and the parabola have two common points
• 19. It is known that the parabola y ^ 2 = 2x (P greater than 0), passing through point (1,0) as a straight line with slope k, intersects parabola at two points a and B. the symmetric point of point a about X axis is C It is known that the parabola y ^ 2 = 2x (P is greater than 0), passing through point (1,0) as a straight line with slope k, l intersects the parabola at two points a and B, the symmetric point of point a about X axis is C, and the straight line BC intersects X axis at Q. try to prove that when k changes, q is a fixed point
• 20. (1) translate the parabola Y1 = 2x2 two units to the right to get the parabola Y2 Ask 2010 Zhejiang Yiwu high school entrance examination question 16 very detailed analysis? 16. (1) translate the parabola Y1 = 2x2 two units to the right, and get the result For the image of parabola Y2, then y2 = ■; (2) As shown in the figure, P is a moving point on the symmetry axis of the parabola Y2, The straight line x = t is parallel to the Y axis, and is respectively parallel to the straight line y = x The parabola Y2 intersects at points a and B. If △ ABP is a parabola Or an isosceles right triangle whose point B is a right vertex If the value of T is sufficient, then t = 0 can be found in the graph. Don't copy the analytic answers they wrote for me