NCERT Solutions for Class 12 Maths Exercise 7.9 hapter 7 Integrals – FREE PDF Download
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NCERT Solutions for Class 12 Maths Chapter 7 Integrals (Ex 7.9) Exercise 7.9
Evaluate the definite integrals in Exercises 1 to 11.
1. 
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=2 Ans.
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Evaluate the definite integrals in Exercises 12 to 20.
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=15∫0110x5x2+1dx+3∫011(5√x)2+12dx=15∫0110x5x2+1dx+3∫011(5x)2+12dx
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=15(log|5(1)2+1|−log|5(0)2+1)+35√(tan−15–√−tan−10–√)=15(log|5(1)2+1|−log|5(0)2+1)+35(tan−15−tan−10)
=15(log6−log1)+35√(tan−15–√−0)=15(log6−log1)+35(tan−15−0)
=15(log6−0)+35√(tan−15–√−0)=15(log6−0)+35(tan−15−0)
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First we evaluate 
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……….(i)
Putting 
From eq. (i), 
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(On dividing)
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where I = 
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……….(i)
Now, I = ……….(ii)
Let 
……….(iii)
Comparing coefficients of 
A + B = –20 ……….(iv)
Comparing constants 3A + B = –15 ……….(v)
On solving eq. (iv) and (v), we get A = 
B = 
Putting these values in eq. (iii),
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Putting this value of I in eq. (i),
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= π41024+π2+2π41024+π2+2 Ans.
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[Applying Product Rule on first definite integral]
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Choose the correct answer in Exercises 21 and 22.
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equals:
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Therefore, option (D) is correct.
22. 
equals:
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Therefore, option (C) is correct.
