Whether to use quotation marks in VFP field validity rules and expressions

A valid logical expression should be written in the field validity rule
Such as unit price > = 0
Or gender = male or gender = female

RELATED INFORMATIONS

1. Let f (x) be a periodic function, and the minimum positive period is 2, and f (1 + x) = f (1-x), if - 1
2. It is known that the domain of function y = f (x) is R +, f (8) = 3. For any x ∈ R, f (x1x2) = f (x1) + F (x2) conjecture expression Reasonable reasoning content, .' | | / | |/-.( | |\_ ._ \ | | \ \`;| | > |/| | / // | | |// | | \(\ | | `` | | | | | | | | | \\ _ _ \\| \// |//_ _ \// _ ^ `^`^ ^`` `^ ^` ``^^` `^^` `^ `^
3. Given that the function f (x) is an odd function and the domain of definition is r, when x > = 0, f (x) = - x2-2x, find the expression of F (x) in the domain of definition
4. Given the function f (x) = 2x-1, find the expression of F (x2) I feel dizzy=
5. Given f (x-1 / x) = x2 + 1 / X2, the expression of function f (x) is
6. What is asin (Wx + φ) + B = (ymax + yman) / 2
7. It is known that the period of F (x) = asinwx + bcoswx, (W > 0) defined on R is Π, and f (x)
8. Let f (x) = asinwx plus bcoswx (W greater than 0) be a function defined on R. Let f (x) be less than or equal to f (12 / 12) = 4 Let f (x) = asinwx plus bcoswx (W greater than 0) be a function defined on R, and f (x) be less than or equal to f (12 / 12) = 4. Let the real numbers X1 and X2 belong to (0, pie), and f (x1) = f (x2) = negative 2, then find X1 plus x2
9. It is known that the period of F (x) = asinwx + bcoswx, (W > 0) defined on R is Π, and f (x)
10. What is the period of simple harmonic motion related to
11. Let L = 16, M = 15, NL = 19, n = L-M, the value of the expression n & n-1? What does n & n mean?
12. The difference between database table and free table
13. What's the difference between free table and database in VFP? How many parts does a table consist of? What are the steps to create a table?
14. As shown in the figure, in the plane rectangular coordinate system, the image of quadratic function y = x + BX + C intersects with X axis and points a and B, point a is on the left side of the far point, the coordinate of point B is (3,0), intersects with y axis and points c (0, - 3), and point P is a moving point on the parabola below the straight line BC 1. Find the expression of this quadratic function 2. Connect Po and PC, and fold △ POC along CO to get quadrilateral pop ˊ C. is there a point P to make quadrilateral pop ˊ C diamond?
15. Given that M belongs to R, f (x) = (m-1) x ^ 1 / M is a power function. (1) the expression for finding f (x): (2) if f (2-A ^ 2) ≥ f (a), find the value range of real number a
16. 9 (X-Y) ^ 2 + m + 4 is a complete square expression, and M expression is obtained
17. How to understand that an event with probability equal to 1 is not necessarily an inevitable event, and an event with probability equal to 0 is not necessarily an impossible event, please elaborate in detail and give examples
18. Probability of relatively independent events in Mathematics There are 10 balls from No.0 to No.9, which are pulled out one at a time and then put back. The probability of pulling 1 is 1 / 10, that is to say, there will be one in 10 times. Then I want to know the probability of pulling 1 only after 20 times and how much is it after 30 times
19. For example: the event with probability 1 is not necessarily inevitable, and the event with probability 0 is not necessarily impossible
20. On the probability basic event space of mathematics compulsory 3 Take any 4 out of 50 products with 6 defective products, and observe the number of defective products. The basic event space is