Let \(y=\dfrac{x^2-x}{e^x}\).
Find and simplify \(\dfrac{dy}{dx}\). (2 marks)
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Let \(y=\dfrac{x^2-x}{e^x}\).
Find and simplify \(\dfrac{dy}{dx}\). (2 marks)
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\(\dfrac{-x^2+3x-1}{e^x}\)
\(\text{Using the quotient rule:}\)
| \(\dfrac{dy}{dx}\) | \(=\dfrac{e^x(2x-1)-(x^2-x)e^x}{(e^x)^2}\) |
| \(=\dfrac{e^x(-x^2+3x-1)}{e^{2x}}\) | |
| \(=\dfrac{-x^2+3x-1}{e^x}\) |
Differentiate with respect to `x`:
`e^(tan(2x))` (2 marks)
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`2 sec^2(2x)* e^(tan(2x))`
| `y` | `=e^(tan(2x))` |
| `dy/dx` | `= d/(dx)tan(2x) xx e^(tan(2x))` |
| `= 2 sec^2(2x)* e^(tan(2x))` |
Let `f(x) = (e^x)/((x^2-3))`.
Find `f^{′}(x)`. (2 marks)
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`{e^x(x^2-2x-3)}/{(x^2-3)^2}`
`text(Let) \ \ u = e^x \ \ => \ \ u^{′} = e^x`
`v = (x^2-3) \ \ => \ \ v^{′}= 2x`
| `f′(x)` | `= {e^x(x^2-3)-2x e^x}/{(x^2-3)^2}` |
| `= {e^x(x^2-2x-3)}/{(x^2-3)^2}` |
Let `y = (2e^(2x)-1)/e^x`.
Find `(dy)/(dx)`. (2 marks)
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`(dy)/(dx) = 2e^x + e^(-x)`
`text(Method 1)`
| `y` | `= 2e^x-e^(-x)` |
| `(dy)/(dx)` | `= 2e^x + e^(-x)` |
`text(Method 2)`
| `(dy)/(dx)` | `= (4e^(2x) ⋅ e^x-(2e^(2x)-1) e^x)/(e^x)^2` |
| `= (4e^(3x)-2e^(3x) + e^x)/e^(2x) ` | |
| `= (2e^(2x) + 1)/e^x` |
Differentiate `e^x/(x + 1)`. (2 marks)
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`(xe^x)/(x + 1)^2`
`y = e^x/(x + 1)`
`text(Differentiate using quotient rule:)`
`u = e^x\ \ \ \ \ \ \ v = x + 1`
`u^{\ prime } = e^x\ \ \ \ \ v^{\ prime }= 1`
| `(dy)/(dx)` | `= (u^{\ prime } v-u v ^{\ prime })/v^2` |
| `= (e^x(x + 1)-e^x ⋅ 1)/(x + 1)^2` | |
| `= (x e^x)/(x + 1)^2` |
What is the derivative of `e^(x^2)`?
`C`
| `y` | `= e^(x^2)` |
| `(dy)/(dx)` | `= 2x e^(x^2)` |
`=> C`
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a. `e^(3x) (1 + 3x)`
b. `6e^6`
a. `y = xe^(3x)`
`text(Using product rule:)`
`(dy)/(dx)= x · 3e^(3x) + 1 · e^(3x)= e^(3x) (1 + 3x)`
b. `int_0^2 e^(3x) (3 + 9x)\ dx`
`= 3 int_0^2 e^(3x) (1 + 3x)\ dx`
`= 3 [x e^(3x)]_0^2`
`= 3 (2e^6-0)= 6e^6`
Differentiate `(e^x + x)^5`. (2 marks)
`5 (e^x + 1) (e^x + x)^4`
| `y` | `= (e^x + x)^5` |
| `(dy)/(dx)` | `= 5 (e^x + x)^4 xx d/(dx) (e^x + x)` |
| `= 5 (e^x + x)^4 xx (e^x + 1)` | |
| `= 5 (e^x + 1) (e^x + x)^4` |
Differentiate with respect to `x`:
`(2x)/(e^x + 1)` (2 marks)
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`{2(e^x + 1-xe^x)}/(e^x + 1)^2`
`y = (2x)/(e^x + 1)`
`u= 2x\ \ \ \ \v= e^x + 1`
`u ^{\ prime}=2\ \ \ \ \ v^{\ prime}= e^x`
| `(dy)/(dx)` | `= (u^{\ prime} v-uv^{\ prime})/v^2` |
| `= {2(e^x + 1)- 2x(e^x)}/(e^x + 1)^2` | |
| `= (2e^x + 2-2x * e^x)/(e^x + 1)^2` | |
| `= {2(e^x + 1-xe^x)}/(e^x + 1)^2` |
Differentiate with respect to `x`.
`(e^x+1)^2`. (2 marks)
`2e^x(e^x+1)`
| `y` | `=(e^x+1)^2` |
| `dy/dx` | `=2(e^x+1)^1xxd/(dx) (e^x+1)` |
| `=2e^x(e^x+1)` |
Differentiate `(3+e^(2x))^5`. (2 marks)
`10e^(2x)(3+e^(2x))^4`
`y=(3+e^(2x))^5`
| `(dy)/dx` | `=5(3+e^(2x))^4 xx d/(dx)(3+e^(2x))` |
| `=5(3+e^(2x))^4 xx 2e^(2x)` | |
| `=10e^(2x)(3+e^(2x))^4` |
Differentiate `x^2e^x` (2 marks)
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`xe^x(x+2)`
`text{Using the product rule}`
`text(Let)\ \ u=x^2,\ \ \ \ \ \ u^{\ prime}=2x`
`text(Let)\ \ v=e^x,\ \ \ \ \ \ v^{\ prime}=e^x`
| `{d(uv)}/dx` | `=u^{\ prime} v+v^{\ prime} u` |
| `=2x e^x +x^2 e^x ` | |
| `=xe^x(x+2)` |