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dfreseniusBest ResponseYou've already chosen the best response.1
dw:1361089150658:dw
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
dw:1361089181888:dw
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
or would it be cos^xcos5x
 one year ago

dumbcowBest ResponseYou've already chosen the best response.0
no cant combine them...it would just be \[\cos(5x)  \cos^{2} x \cos(5x)\]
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
so left integral is easy
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
hmm no i cant do that
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
that 5x is just blowing my mind
 one year ago

dumbcowBest ResponseYou've already chosen the best response.0
yeah im not sure of way to do it without expanding out the cos(5x) ..... which would be messy
 one year ago

hartnnBest ResponseYou've already chosen the best response.2
huh ? integral of cos 5x is just sin 5x/5 +c .
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
dw:1361089595564:dw
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
yA i know that integral, but its the cos^2 that is messin me up
 one year ago

hartnnBest ResponseYou've already chosen the best response.2
ok, you need to used \(\sin^2x = (1 \cos2x )/2\)
 one year ago

hartnnBest ResponseYou've already chosen the best response.2
then, for cos 2x cos 7x there is a standard formula for , cos A cos B =...
 one year ago

dumbcowBest ResponseYou've already chosen the best response.0
ahh i always forget sum to product rules ... anyway, here is solution http://www.wolframalpha.com/input/?i=integrate+sin^2%28x%29+cos%285x%29+dx
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
dw:1361090139384:dw
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
ok so here is another, im thinking with this one i can multiply by a 1/2 and use the identity sin2x
 one year ago

hartnnBest ResponseYou've already chosen the best response.2
sin x cos x = (sin 2x) /2 then we have formula for sin A cos B
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
dw:1361090244648:dw
 one year ago

sami21Best ResponseYou've already chosen the best response.0
for the first question by parts can also be used . \[\Large \frac{1}{5}\sin^2(x)\sin(5x)\frac{2}{5}\int\limits \sin(x)\sin(5x)\cos(x)dx\]
 one year ago

.Sam.Best ResponseYou've already chosen the best response.0
\[( \sin A ) ( \sin B )=\frac{1}{2} (\cos (A B )\cos (A +B ))\]
 one year ago

.Sam.Best ResponseYou've already chosen the best response.0
But there's still a lot of work if you do this
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
dw:1361090429038:dw
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
dw:1361090501054:dw
 one year ago

hartnnBest ResponseYou've already chosen the best response.2
why  *minus* in between ?
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
integral of sin is cosx
 one year ago

hartnnBest ResponseYou've already chosen the best response.2
both of  from that you have factored out, right ? to make 1/4 ?
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
well, before i took integral
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
dw:1361090806081:dw
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
those will both be negative right?
 one year ago

hartnnBest ResponseYou've already chosen the best response.2
integral of those will be negative, yes, right.
 one year ago

dfreseniusBest ResponseYou've already chosen the best response.1
ok thats all i got, thank you so much both of you for helping me out, big test this friday
 one year ago
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