Question
sir i have 2 questions,
1) how to integrate, dx/(x^2 + y^2 )^1/2.
2) target 7, pg -91 derivation (end part in detail).
i will be grateful...
Read 2 Solution.
∫ dx/(x^2 + y^2 )^1/2 can be done by using substitution method ;
first of all we will have to put x = y tanA
then dx = ysec2A dA(differentiating)
putting these values : √(x2+y2) = √(y2tan2A + y2) = ysecA
now dx/(expression) = ysec2A dA/ysecA = ∫ sec A dA
and ∫ sec A dA = ln(tanA + secA)
now as tanA = x/y so, A = tan-1(x/y)
so , ln(√[(x/y) +√(x2/y2 + 1)] simplify this to get the answer
Best SolutionAMIT DAS 12 year ago
is this solution helpfull: 3 0
answer to ur second question:
(1+x)n = 1+ nx , this is known as binomial approxiamtion and is applicable only when x is very very less ( here its given that |z| is >> R hence the value of (r/z)2 will be close to zero .
(always write the whole question as the books may not be available all the time )
AMIT DAS 12 year ago
is this solution helpfull: 3 0