Given that y=3e2x2x+1y = \frac{3\text{e}^{2x}}{2x+1}, find the value of kk for which dydx=kxy2x+1\frac{\text{d}y}{\text{d}x} = \frac{kxy}{2x+1}.

Work through it with AI →

It won't just hand you the answer — it asks where you're stuck.How the checker works

Worked solution

3

1. Differentiate $y$ with respect to $x$ using the quotient rule.

Let u=3e2xu = 3\text{e}^{2x} and v=2x+1v = 2x+1.
dudx=6e2x\frac{\text{d}u}{\text{d}x} = 6\text{e}^{2x}
dvdx=2\frac{\text{d}v}{\text{d}x} = 2

dydx=vdudx−udvdxv2\frac{\text{d}y}{\text{d}x} = \frac{v\frac{\text{d}u}{\text{d}x} - u\frac{\text{d}v}{\text{d}x}}{v^2}
dydx=(2x+1)(6e2x)−(3e2x)(2)(2x+1)2\frac{\text{d}y}{\text{d}x} = \frac{(2x+1)(6\text{e}^{2x}) - (3\text{e}^{2x})(2)}{(2x+1)^2}

2. Simplify the numerator of the derivative.

dydx=12xe2x+6e2x−6e2x(2x+1)2\frac{\text{d}y}{\text{d}x} = \frac{12x\text{e}^{2x} + 6\text{e}^{2x} - 6\text{e}^{2x}}{(2x+1)^2}
dydx=12xe2x(2x+1)2\frac{\text{d}y}{\text{d}x} = \frac{12x\text{e}^{2x}}{(2x+1)^2}

3. Express the derivative in the given form to find $k$.

We are given dydx=kxy2x+1\frac{\text{d}y}{\text{d}x} = \frac{kxy}{2x+1}.
Substitute y=3e2x2x+1y = \frac{3\text{e}^{2x}}{2x+1} into this expression:
dydx=kx2x+1(3e2x2x+1)=3kxe2x(2x+1)2\frac{\text{d}y}{\text{d}x} = \frac{kx}{2x+1} \left( \frac{3\text{e}^{2x}}{2x+1} \right) = \frac{3kx\text{e}^{2x}}{(2x+1)^2}

Equating the two expressions for dydx\frac{\text{d}y}{\text{d}x}:
12xe2x(2x+1)2=3kxe2x(2x+1)2\frac{12x\text{e}^{2x}}{(2x+1)^2} = \frac{3kx\text{e}^{2x}}{(2x+1)^2}

Comparing the coefficients of xe2xx\text{e}^{2x}:
12=3k12 = 3k
k=4k = 4

Answer

k=4k = 4

AI analysis — may contain mistakes.

Worked this one out on paper? Snap your steps and Gigle's AI math checker will circle the step where it went wrong.

More questions on this topic

  1. 1Given that y=3ln⁡2xx2y = \dfrac{3\ln 2x}{x^2} for x>0x>0. Show that dydx=3x3(1−2ln⁡2x).\dfrac{dy}{dx} = \dfrac{3}{x^3}\left(1 - 2\ln 2x\right). He…
  2. 2A curve has the equation y=2x−33x+4y = \frac{2x - 3}{3x + 4}, where x≠−43x \ne -\frac{4}{3}. The normal to the point PP on the cur…
  3. 3Given that y=6x22−5xy = \frac{6x^2}{2-5x}, find the range of values of xx for which yy is a decreasing function of xx.
  4. 4已知函数f(x)=ex−1f(x)={{e}^{x}}-1,g(x)=sin⁡x(1)g(x)=\sin x(1)判断F(x)=f(x)−g(x)F(x)=f(x)-g(x)在x∈[0,+∞)x\in[0,+\infty)上零点的个数; (2)当x∈[0,π]x\in[0,\pi]时,f(x)⩾ag(x)(a∈R)f(x)\geqslant ag(x)(a\in R)…
  5. 5The equation of a curve is given by y=5xe2x+1y = 5xe^{2x+1}. Find dydx\frac{dy}{dx}. Hence, find ∫xe2x+1 dx\int xe^{2x+1} \text{ d}x. Det…