Mathematics
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OpenStudy (anonymous):
Find the derivative of the trigonometric function.
y=2xsinx+x^2cosx
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OpenStudy (diyadiya):
\[y'=\frac{d}{dx}(2xsinx)+ \frac{d}{dx}x^2cosx \]
OpenStudy (cwrw238):
use product rule
OpenStudy (anonymous):
product rule for addition?
OpenStudy (diyadiya):
use product rule for each term
OpenStudy (anonymous):
ah ok
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OpenStudy (cwrw238):
no - apply product rule to each of the two terms
- looks like diyad is doing that now
OpenStudy (diyadiya):
First do \( \frac{d}{dx}(2xsinx) \) & then \( \frac{d}{dx}(x^2cosx) \)
OpenStudy (diyadiya):
do you know how to do derivative of 2xsinx ?
OpenStudy (cwrw238):
d (uv)dx = u* dv/dx + v* du/dx where u and v are function of x
OpenStudy (anonymous):
so
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OpenStudy (anonymous):
2xsix+x^2cosx=2sinx+3xcosx+2xcosx-x^2sinx
OpenStudy (anonymous):
2sinx oops
OpenStudy (diyadiya):
Nope
OpenStudy (anonymous):
2xsinx
OpenStudy (anonymous):
4xcosx+2sinx-x^2sinx
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OpenStudy (anonymous):
4xcosx+sinx(2-x^2)
OpenStudy (anonymous):
i mistyped a bunch at first lol
OpenStudy (diyadiya):
\[\frac{d}{dx} (2xsinx)= 2 \frac{d}{dx}(xsinx) =2[x \frac{d}{dx}sinx+sinx \frac{d}{dx}x]\]
OpenStudy (anonymous):
my last answer is correct
OpenStudy (anonymous):
4xcosx+sinx(2-x^2)
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OpenStudy (anonymous):
atleast thats what the books says in the back.
OpenStudy (diyadiya):
\[ \frac{d}{dx}(2xsinx)=2[xcosx+sinx]\]
OpenStudy (anonymous):
y=2xsinx+x^2cosx
= 2sinx+2xcosx+2xcosx-x^2sinx
= 4xcosx +2sinx - x^2sinx
= 4xcosx + sinx(2-x^2)
OpenStudy (cwrw238):
thats correct ChrisV
OpenStudy (anonymous):
thanks guys
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OpenStudy (diyadiya):
oh sorry i thought you were taling about the derivative of 2xsinx
OpenStudy (anonymous):
did not know i could use product rule on both sides
OpenStudy (anonymous):
better to learn than wonder :)
OpenStudy (cwrw238):
yep - whenever you have a product of two functions the rule applies