# The proof - practice problems

The proof is a convincing demonstration in mathematics that a statement is true under certain conditions.Direction: Solve each problem carefully and show your solution in each item.

#### Number of problems found: 33

- Prove 2

Prove that the minimum number of straight single cuts/strokes needs to divide a given right-angled triangle or an obtuse-angled triangle into a collection of all acute-angled triangles is seven(7). - Triangle 80994

In the triangle, ABC, the angles alpha and beta axes subtend the angle phi = R + gamma/2. R is a right angle of 90°. Verify. - Five-minute 80951

Karel has an average grade of exactly 1.12 from five-minute episodes. Prove that at least 22 of them have one. - Janice

Janice said that when you multiply a fraction less than 1 by a nonzero whole number, the product is always less than the whole number. Do you agree? Explain. - Circumscribing 80498

Given is an acute-angled triangle ABC. On the half lines opposite to BA and CA lie successively the points D and E such that |BD| = |AC| and |CE| = |AB|. Prove that the center of the circle circumscribing triangle ADE lies on the circle circumscribing tri - Smallest 79434

Find the smallest natural x such that 2x is the square and 3x is the third power of a natural number. - Constructed 77874

Squares are constructed above the overhangs and the transom. Connecting the outer vertices of adjacent squares creates three triangles. Prove that their contents are the same. - Bisector 2

ABC is an isosceles triangle. While AB=AC, AX is the bisector of the angle ∢BAC meeting side BC at X. Prove that X is the midpoint of BC. - Fraction and ratios

Fraction and ratios are different names for the same thing. - Simplify logarithm expr

Given that logxU + logxV =p and logxU - logxV =q Prove that U=x^½(p+q) - Directly 55591

If n is a natural number that gives a division of 2 or 3 when divided by 5, then n gives a residue of 4 when divided by 5. Prove directly - Indirectly: 55581

Prove indirectly: No odd natural number is divisible by four. - Decreasing 36183

Prove that the sequence {3 - 4. n} from n = 1 to ∞ is decreasing. - Justification 8468

The natural number n has at least 73 two-digit divisors. Prove that one of them is the number 60. Also, give an example of the number n, which has exactly 73 double-digit divisors, including a proper justification. - Workers

Three factory operators produced 480 units in 50 minutes. How many hours worked? I'm trying to prove or disapprove of the idea that the company tells me it's 2.5 hours. So what is right? Thank you, Petra. - Inequality 7320

Let a, b, and c be positive real numbers whose sum is 3, each of which is at most 2. Prove that the inequality holds: a2 + b2 + c2 + 3abc - Odd/even number

Pick any number. If that number is even, divide it by 2. If it's odd, multiply it by three and add one. Now repeat the process with your new number. If you keep going, you'll eventually end up at one every time. Prove. - Prove

Prove that k1 and k2 are the equations of two circles. Find the equation of the line that passes through the centers of these circles. k1: x²+y²+2x+4y+1=0 k2: x²+y²-8x+6y+9=0 - Sum of inner angles

Prove that the sum of all inner angles of any convex n-angle equals (n-2).180 degrees. - Equilateral cylinder

A sphere is inserted into the rotating equilateral cylinder (touching the bases and the shell). Prove that the cylinder has both a volume and a surface half larger than an inscribed sphere.

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