69 Answered Questions for the topic Proof

Proof Induction


induction proof

proof that for n>=2 it is true that:2^(1+2+3+...+n)>n!

are sine and cosine equal for non-acute complementary angles?

for example, when writing a proof, is it logical to write the following:cos(-ø)=sin(π/2+ø) (∵ the cosine of an angle is equal to the sine of its complementary angle)I ask because this... more


Vector Proof Question

Suppose v and w are vectors in Rn . Show that || v − w || ≥ || v || − || w ||

How can I prove this mathmatical induction?

∑j=1n 2j = 2(2n-1)

Why can't programs be proven?

Why can't a computer program be proven just as a mathematical statement can? A mathematical proof is built up on other proofs, which are built up from yet more proofs and on down to axioms - those... more


Need math help, please! Proof

Given: Quadrilateral has diagonal  which splits the quadrilateral into two congruent isosceles triangles.Prove:  is a rhombus.
Proof Logic


I need help finding out how to solve this proof

Can you prove anything in philosophy?

I don't understand philosophy very well, and so I am wondering whether you can "prove" anything in philosophy. It always seems you can go a layer down, and find another question, almost endlessly... more


Does a negative claimant have a burden of proof?

I have often heard it said that the burden of proof is on the positive claimant but not on the one making a negative claim. A person claiming, "God exists" has a burden of proof but not a person... more


Trigonometry Identity II

Please fully complete this identity, step-by-step with as much detail as necessary!(Note: 'θ' (theta) just means angle. It can be replaced with 'x'.)(1 ÷ cos θ + 1) - (1 ÷ cos θ - 1) = (2 ÷ sin2 θ)


Trigonometry Identity

Please fully complete this identity, step-by-step with as much detail as necessary! (Note: 'θ' (theta) just means angle. It can be replaced with 'x'.)Prove that (cos θ - tan θ)2 - 2 ≡ tan2 θ - (1 +... more
Proof Geometry


URGENT If m<2+m<3+m<4=180* then prove that m<1=m<3+m<4

A m<2 + m<3 + m<4 = 180*B m<1 + m<2 =180*C m<1 + m<2 = m<2 + m<3 + m<4D m<1 + m<2 - m<2 = m<2 +m<3 + m<4 - m<2E m<1 = m<3 + m<4

Let G be a group and a∈G. Prove that <a>C(a) ≤ G where <a>C(a) = {bc|b∈<a>, c∈C(a)}?

Need to prove that <a>C(a) ≤ G where <a>C(a) = {bc|b∈<a>, c∈C(a)}



prove      Cos x       cot x _____ -  ______   = cos 2 x  _  cot 2 x    sec x       tan x.      


Can I use proof where I assume the statement to be true and then arrive at a known fact.

Prove x/y + y/x ≥ 2. Now the book gives (x-y)2 ≥0 and from there derived the above, hence proving it. I understand that, because you start at a known fact and end up at the thing you are trying to... more

Triangle Angle Bisector Proof

Given: Triangle ABD is an equilateral triangle and E is the midpoint of segment AD.   Prove: Segment EB bisects angle DBA.   Prove: Segment EB is perpendicular to Segment AD Please also... more


Triangle Congruence Proof

Prove: Triangle ABF is congruent to Triangle EHG   Given: angle H = angle B and segments FG = EA, angles HEG and FAB are right angles, 

Simplify using logic of laws, Question "~(~b∧a)∧(b∨a) "

~ mean not ^ mean and ∨ mean or   Help me pls

Prove by Induction question, 2+6+18+...+ 2.3^n-1 = (3^n)-1

Can anyone help me solving this problem, Im really really lost. Thank you

Direct proof question, "The product of an even integer and an odd integer is even".

I didnt understand  Let say X = 2a +1 while y = 2b+1   Why you need to multiply xy rather x+y, as you can see below: XY = (2a+1)(2y+1) <- correct X+Y = 2a+1+2y+1 <- Incorrect   Can you... more


Given HD=JD and HC=JB prove HB=JC

Need help with this geometryproof please help.  


How do I solve for this 8PC=PQ

A is the midpoint of PQ, B is the midpoint of PA, and C is the midpoint of PB


proof that x+y=2xy

Proof for the equation that x+y=2xy  using whatever method.


Let a and b be positive rational numbers. Prove that if √a+√b is rational, so is √a

I do  know how to solve this problem. Can you show the steps in solving it. What do i substitute for a and b

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