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IIT study group 17 Online
Parth (parthkohli):

Ratio and proportion.

Parth (parthkohli):

@gudden

Parth (parthkohli):

(I'm asking this on their behalf due to some problems on their end.)

Parth (parthkohli):

If\[\dfrac{x}{a}=\dfrac{y}{b}=\dfrac{z}{c}\]then\[\frac{ x ^{3} + a ^{3} }{ x ^{2} + a ^{2}} + \frac{ y ^{3} + b ^{3}} {a ^{2} + b ^{2} } + \frac{ z ^{3} + c ^{3}}{ z ^{2} + c ^{2} } = \frac{ (x+y+z)^{3} + (a+b+c)^{3} }{ (x+y+z)^{2} +(a +b+c)^{2} }\]

Parth (parthkohli):

Let's say that\[\dfrac{x}{a}=\dfrac{y}{b}=\dfrac{z}{c} =k\]then\[x=ka\]\[y=kb\]\[z=kc\]

OpenStudy (gudden):

yeah and then replacing these values of x,y and z in the actual equation / LHS we can get the RHS :p Thanks for the help...:) I needed the starting step badly..! ( was sorta, puzzled with what to start with :) )

Parth (parthkohli):

We probably need a little bit of manipulation on this\[\dfrac{(ka + kb + kc)^3 + (a+b+c)^3}{(ka + kb + kc)^2 + (a+b+c)^2}\]\[=\dfrac{ (k^3+1) \left(a + b + c\right)^3}{(k^2+1)(a + b + c)^2}\]\[=\dfrac{k^3+1}{k^2+1}(a+b+c)\]You'll get the same expression for the LHS.

Parth (parthkohli):

Yup, that's right.

Parth (parthkohli):

Where are you doing these problems from?

OpenStudy (gudden):

Do you want them ?? They are actually in my booklet!

OpenStudy (gudden):

Most of them are calculus based, but the last question at the page is of the old concepts...( those done in 9th and 10th)

OpenStudy (gudden):

*at every page

Parth (parthkohli):

Which booklet?

OpenStudy (gudden):

Booklet of our Tuition center..!

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