Mathematics
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OpenStudy (anonymous):
Differentiate:
x^3(sin(5x)^2
Help please
11 years ago
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OpenStudy (anonymous):
you have to use product rule and chain rule
11 years ago
OpenStudy (anonymous):
\[x ^{3} \times \sin(5x)^{2}\]
11 years ago
OpenStudy (anonymous):
right?
11 years ago
OpenStudy (anonymous):
yes got that bit :)
11 years ago
OpenStudy (anonymous):
please stay with me here
11 years ago
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OpenStudy (anonymous):
thank you :)
11 years ago
OpenStudy (anonymous):
lets first find dy/dx of sin(5x)^2
11 years ago
OpenStudy (anonymous):
can you work on that?
11 years ago
OpenStudy (anonymous):
2sin(5x) * 5?
11 years ago
OpenStudy (anonymous):
sorry cos
11 years ago
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OpenStudy (anonymous):
nooooo wrong
11 years ago
OpenStudy (anonymous):
\[dy/dx =\sin(5x)^2= 2\sin(5x)\cos(5x)\]
11 years ago
OpenStudy (anonymous):
now find dy/dx of x^3
11 years ago
OpenStudy (anonymous):
3x^2
11 years ago
OpenStudy (anonymous):
correct
11 years ago
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OpenStudy (anonymous):
now apply product rule
11 years ago
OpenStudy (anonymous):
\[U.dv/dx + V.du/dx\]
11 years ago
OpenStudy (anonymous):
let U=x^3
and V=sin(5x)^2
11 years ago
OpenStudy (anonymous):
now apply the formular
11 years ago
OpenStudy (anonymous):
dv/dx=\[2\sin(5x)\cos(5x)\]
11 years ago
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OpenStudy (anonymous):
and du/dx=\[3x^2\]
11 years ago
OpenStudy (anonymous):
now our result will be
11 years ago
OpenStudy (anonymous):
\[2x^3\cos(5x)\sin(5x) + 3x^2\sin(5x)^{2}\]
11 years ago
OpenStudy (anonymous):
whic is same as \[x^2(2xcos(5x)\sin(5x)+3\sin(5x)^2)\]
11 years ago
OpenStudy (anonymous):
and that is the result
11 years ago
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OpenStudy (anonymous):
excellent thank you
11 years ago
OpenStudy (anonymous):
thanks to openstudy
11 years ago
OpenStudy (anonymous):
you didn't differentiate the 5x?
11 years ago
OpenStudy (anonymous):
no
11 years ago
OpenStudy (anonymous):
ok. did a mistake there
11 years ago
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OpenStudy (anonymous):
\[dy/dx = [x^3 *(d/dx) (\sin^2(5x))] + [(\sin^2(5x)) * (d/dx) x^3] \]
11 years ago
OpenStudy (anonymous):
\[ [x^3 * 2\sin(5x) * (d/dx) \sin(5x)] + [(\sin^2(5x)) * 3x^2] \]
11 years ago
OpenStudy (anonymous):
look at this step
\[ [x^3 * 2\sin(5x) * \cos(5x) * (d/dx) 5x] + [(\sin^2(5x)) * 3x^2] \]
11 years ago
OpenStudy (anonymous):
\[ [x^3 * 2\sin(5x) * \cos(5x) * 5] + [(\sin^2(5x)) * 3x^2] \]
11 years ago
OpenStudy (anonymous):
\[ [10x^3 * \sin(5x) * \cos(5x)] + [3x2 * \sin^2(5x)] \]
11 years ago
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OpenStudy (anonymous):
thats the result
11 years ago
OpenStudy (anonymous):
please close the question
11 years ago
OpenStudy (irishboy123):
is this
\[\frac{d (x^3\sin(5x)^2)}{dx} = \frac{d (x^3\sin(25x^2))}{dx}\]
or
\[\frac{d (x^3\sin^2(5x))}{dx}\]
looks like the former, has been done as the latter...
11 years ago