Find the integrating factor of the following first order ODE: dx/dt = -2tx +t.

Firstly rearrange the differential equation to fit the form dx/dt +P(t)x = Q(t). The integrating factor is then found by using the formula:

u = EXP(INTG(P(t))). We know that P(t) = 2t and so by integrating we find that INTG(P(t)) (which means the integral of P(t)) is equal to t2. And so our integrating factor u = et^2.

Note: this is used in solving first order differential equations; by multiplying each term by the integrating factor and then some clever observation, you will see that the equation will now resemble the product rule formula. This can be used to solve the first order ODE as you will see in future questions.

AT

Related Further Mathematics A Level answers

All answers ▸

Simplify i^{4}?


Two planes have eqns r.(3i – 4j + 2k) = 5 and r = λ (2i + j + 5k) + μ(i – j – 2k), where λ and μ are scalar parameters. Find the acute angle between the planes, giving your answer to the nearest degree.


How do you sketch the graph of y=(x-1)/(x+1)?


solve 3sinh^2(2x) + 11sinh(2x) = 4 for x, giving your answer(s) in terms of the natural log.