# Square root

sqrt(81t^4 + 18t^2 +1).can anybody teach me how to factorise this eqn so that the sqrt can be done pls

thanx

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i need to integrate this eqn w.r.t (t).
pls help

nazzard
Gold Member
Hello teng,

make use of the binomial theorem.

$$(a+b)^2=a^2+2ab+b^2$$

The coefficient 81 should be a good hint already.

Regards,

nazzard

Last edited:
nazzard
Gold Member
teng125 said:
i need to integrate this eqn w.r.t (t).
pls help
After you made use of the binomial theorem you will have to integrate a polynomial in t. Do you know how to do that?

Regards,

nazzard

If the t^4 bothers you, substitute t^2 = r in the equation and then factorize the quadratic form. Don't forget to revert to t before you integrate.