Ques. 1JEE Main 2024, 29 January (Evening Shift)
Let the slope of the line 45x+5y+3=0 be 27r1+ 9r22 for some r1, r2 R. Then x 3 ( 3x 8t2 3r2x2-r2x2-r1x3-3x dt ) is equal to .
Answer
12
Solution
Slope =-9 27r1+ 9r22=-9
Let g(x)= 3r2x2-r2x2-r1x3-3x (free of t)
limit = x 3 3x8t2 dtg(x), g(3)=- (27r1+ 9r22 )-9=0 ( 00 )
L'Hôpital: = 8(3)2g'(3), g'(3)= 3r22-6r2-27r1-3=- (27r1+ 9r22 )-3=6
limit = 726=12
Answer: 12