High School Math Logic Problems? Math logic questions high IQ questions

1.The logarithm of a number is negative, and this number is positive. Only positive numbers can be logarithmic, so the negative proposition must be true.

2.Exponential: a b = n, logarithmic log(a) n = both zero negation is a and b are not both zero.

Not all of them are zero. A 0 or B 0, then A 2 + B 2 is a sufficient condition for S, then Q > S (indicating that Q pushes out S); s is the charge of r....then s>r; q is necessary for r....then r>q. i.e., q>s and s>q, i.e., s=q.

Therefore, S is a condition for Q to be sufficient. And S > R > P, so S is a sufficient condition for P, and conversely, P is a necessary condition for S.

This is high school probability, which means that there are six people in total, and the question asks for three men what is the probability. That is, x+3y=6

If the female is set to x and the male is y, the probability of three men together is a third of the probability of being a female being x, and the probability of a male being 3 is a third of the probability of being a female being set to x, and the probability of a male being 3 is a probability of being 3.

Assuming that the amount of grass per cow per day is 1, the amount of grass eaten by 27 cattle for 6 days is 27 6=162;The amount of grass eaten by 23 cows in 9 days is 23 9 = the difference between 162 and (9-6) days of new grass, so the amount of new grass grown in the pasture per day is (207-162) (9-6) = 15

Because the amount of grass eaten by 27 cows in 6 days is 162, the sum of the newly grown grass in these 6 days is 15 6 = 90, so it can be seen that the original amount of pasture is 162-90 = 72

The new grass grows enough for 15 cows to eat for a day, and every day 15 of the 21 cows eat the newly grown grass, and the remaining 21-15 = 6 (heads) eat the original grass. Therefore, the grass on the pasture is enough to eat 72 6 = 12 (days), that is, the grass on this pasture is enough for 21 cows to eat for 12 days.

Comprehensive formula: [27 6-(23 9-27 6) (9-6) 6] [21-(23 9-27 6) (9-6)] = 12 (days).

Hello landlord.

The system of equations ax+by=1 and x 2+y 2=1 has a real solution, which means that the distance from the point (0,0) to the line ax+by=1 is 1, i.e. 1 (a 2+b 2) 1, i.e. a 2 + b 2 1, i.e. a 2 + b 2 1

So, if a 2 + b 2 1, then the system of equations ax+by=1 and x 2+y 2=1 have real solutions; If the system of equations ax+by=1 and x 2+y 2=1 have real solutions, then a 2 + b 2 1

Therefore, it is a sufficient condition, choose C

Hope you're satisfied.

Xiaoxin did a good thing.

It can be assumed that someone is doing good deeds and analyzing it.

For example, it is Xiaohong who does good deeds, then: Xiaohong tells lies, Xiaofang tells the truth, and Xiaoxin tells the truth. Not on topic.

If it is Xiaofang, then: Xiaohong tells the truth, Xiaofang tells lies, and Xiaoxin tells the truth. Wrong.

That can only be Xiaoxin, and it can also be judged in the same way: Xiaohong tells a lie, Xiaofang tells the truth, and Xiaoxin tells a lie.

The small new dry, the elimination method upstairs is already very specific.

Proposition p: "A+B 2 (ab),(a,b r)".

a, b r" is the major premise of this proposition, and the proposition is established for arbitrary real numbers a,b, which is a full proposition.

When writing the negation of a proposition, the major premise remains the same, and the full name of the negation of the proposition is an existential proposition, not p: "there are real numbers a, b r, a+b<2 (ab)".

When judging whether a written proposition is correct, use: the proposition and its negation must be one true and one false.

There is a, b a+b less than or equal to 2 root number ab