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Are the integers a group under addition? How about multiplication?

There are 4 things we need for a group: associativity, the existence of an identity, inverses in the group and closure. The integers are definitely associative under this operation as addition is associative...
DC
7231 Views

The ODE mx'' + cx' + kx = 0 is used to model a damped mass-spring system, where m is the mass, c is the damping constant and k is the spring constant. Describe and explain the behaviour of the system for the cases: (a) c^2>4mk; (b) c^2=4mk; (c) c^2<4mk.

In the case c 2 &gt;4mk, the characteristic equation has two distinct real roots; this represents overdamping. The system does not oscillate, and x approaches zero as time approaches infinity.In the case c 2...
OG
14451 Views

How do I determine whether a system of 3 linear equations is consistent or not?

First, form the system into a 3x3 matrix using the coefficients. Find the determinant of this matrix.If the determinant =/= 0, then the matrix is singular and has a unique solution. The system is consistent ...
22948 Views

Prove by induction that f(n) = 2^(k + 2) + 3^(3k + 1) is divisible by 7 for all positive n.

First we establish our base case: f(0) = 2 2 + 3 1 = 4 + 3 = 7, so clearly f(0) is divisible by 7.Now. by the inductive hypothesis. we assume that f(k) is divisible by 7, and attempt to show that this implie...
WP
3539 Views

How to solve a standard first order differential equation?

First we must ensure that the differential is i the standard form of y' + p(x) y = f(x)The we use the integration factor I(x) = e to the integral of p(x)we then realise that if we differentiate this we will ...
JB
3056 Views