Mathematics
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OpenStudy (anonymous):
plase solve and explain the question ill post to down :
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OpenStudy (anonymous):
\[\int\limits_{}\sqrt{x}\sqrt{a^{2}x^{2}}dx\]
OpenStudy (amistre64):
ax.sqrt(x) dx; u = sqrt(x); u^2 = x; 2u du = dx ..... maybe
a.u^2.u.2u.du
OpenStudy (amistre64):
{S} 2a.u^4.du ; the 2a acts like a constant perhaps?
\[\frac{2au^5}{5}\]
OpenStudy (amistre64):
u^5 = u^2.u^2.u = x.x.sqrt(x)
\[\frac{2a}{5}x^2\sqrt{x}+C\]
maybe
OpenStudy (anonymous):
maybe :)
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OpenStudy (amistre64):
it works lol
OpenStudy (anonymous):
u took u = sqrt(x) so that it been u^2*a*u ^^ then its u^3*adx
OpenStudy (amistre64):
\[\frac{2a}{5}*(2x\sqrt{x}+\frac{x^2}{2\sqrt{x}})\]
OpenStudy (anonymous):
why isnt \[\sqrt{x}\times \sqrt{x^3}=x^2\]?
OpenStudy (anonymous):
and du =u^2 so its now u^3.a.u^2 then its u^5.a / 5 + c
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OpenStudy (anonymous):
if the problem says (my eyes not what they ought to be)
\[\int\sqrt{x}\sqrt{a^2x^3}dx\] then isnt this the same as
\[a\int x^2 dx\]?
OpenStudy (anonymous):
just get
\[\frac{ax^3}{3}\] and be done
OpenStudy (anonymous):
nono its X^2 not X^3 in this sqrt :D
OpenStudy (amistre64):
\[\frac{2a}{5}(\frac{4x^2+x^2}{2\sqrt{x}})=\frac{2a}{5}(\frac{5x^2}{2\sqrt{x}})\]
\[2a(\frac{x^2\sqrt{x}}{2x})=a(x\sqrt{x})=ax\sqrt{x}\]
OpenStudy (anonymous):
ooooooooooooooh sorry
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OpenStudy (anonymous):
i think its \[a*u^{5}/5\]
OpenStudy (anonymous):
and + C
OpenStudy (amistre64):
its:
2a x^5
------ +C :)
5
OpenStudy (anonymous):
then i believe you get
\[\frac{2a}{5}\sqrt{x^5}\]
OpenStudy (anonymous):
amistre root over the
\[x^5\]
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OpenStudy (anonymous):
2 ?? where this 2 came from ?? i thought that dx was du^2
OpenStudy (anonymous):
forget u and du etc
OpenStudy (anonymous):
just rewrite w/ exponents and use power rule
OpenStudy (anonymous):
\[\sqrt{x}\sqrt{a^2x^2}=\sqrt{a^2}x^{\frac{3}{2}}\]
OpenStudy (anonymous):
hmm , why u don't get a^2 out of the swrt?
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OpenStudy (anonymous):
hmm , why u don't get a^2 out of the swrt?
OpenStudy (anonymous):
because it is always possible that a < 0
OpenStudy (anonymous):
and i don't want to fret about rewriting as |a|
OpenStudy (anonymous):
wel but ^2 always will equal to +
OpenStudy (anonymous):
so i left it in the redical
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OpenStudy (anonymous):
exactly. which is why i cannot pull it out
OpenStudy (anonymous):
because if i write it as
\[a x^{\frac{3}{2}}\] this would be incorrect if say a = -3
OpenStudy (anonymous):
satalllite i think its easier to define ıu and du :D
OpenStudy (anonymous):
what?
OpenStudy (anonymous):
just have
\[\int x^{\frac{3}{2}}dx=\frac{2}{5}x^{\frac{5}{2}}\] finish
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OpenStudy (anonymous):
well its goo dtoo :D
OpenStudy (anonymous):
just use power rule that is all. but of course you are free to use whatever
OpenStudy (anonymous):
thanks :D