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NCERT Class XII Mathematics Chapter - - Solutions

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Exercise - 7.4
Integrate the functions in Exercises 86 to 108.
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Question : 100 of 271
Marks: +1, -0
1(x−a)(x−b)\frac{1}{\sqrt{(x-a)(x-b)}}
Solution:  
Let I=∫dx(x−a)(x−b)I=\int\frac{dx}{\sqrt{(x-a)(x-b)}}
=∫dxx2−(a+b)x+ab=\int\frac{dx}{\sqrt{x^2-(a+b)x+ab}}
=∫dxx2−2(a+b2)x+(a+b2)2+ab−(a+b2)2=\int\frac{dx}{\sqrt{x^2-2\left(\frac{a+b}{2}\right)x+\left(\frac{a+b}{2}\right)^2+ab-\left(\frac{a+b}{2}\right)^2}}
=∫dx(x−(a+b2)2)−(a−b2)2=\int\frac{dx}{\sqrt{\left(x-\left(\frac{a+b}{2}\right)^2\right)-\left(\frac{a-b}{2}\right)^2}}
=log⁡∣(x−a+b2)+(x−(a+b2)2)−(a−b2)2∣+C=\log\left| \left(x-\frac{a+b}{2}\right) + \sqrt{\left(x-\left(\frac{a+b}{2}\right)^2\right)-\left(\frac{a-b}{2}\right)^2} \right| + C
=log⁡∣(x−a+b/2)+√(x−a)(x−b)∣+C=\log{|(x- {a+b}/2) +√{(x-a)(x-b)}|}+C
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