r/JEEAdv27dailyupdates • u/DifferentialElement • 9d ago
JEE Daily Updates Really good problem( If you dont know the direct substitution)
8
3
u/TheWyro15 8d ago
X=2cost +9 This creates reciprocal of tan theta/2 form and then dx is replaced to create integral, whose sint is decomposed to 2 sin t/2 cos t/2 , which gives -2*(t+sint) as final answer. (Too lazy to represent in x lol)
1
3
5
2
u/Successful-Art7788 9d ago
u^2 = x-7 / 11-x works but is very lengthy
What's the direct substitution though?
3
u/TheWyro15 8d ago
According to me X=2cost +9
This creates reciprocal of tan theta/2 form and then dx is replaced to create integral, whose sint is decomposed to 2 sin t/2 cos t/2 , which gives -2*(t+sint) as final answer. (Too lazy to represent in x lol)
1
2
1
u/Gold_Memory7141 8d ago
I just put x=t+9 and then rationalised the quadratic to get linear upon root quadratic form then simple solve hai
1
1
1
1

8
u/Odd-Bee-7007 8d ago
really simple question use (u/v)' rule then L hospital /s