Question
The equation of the tangent to the curve y=b e^ -x/a at the point where it crosses the y -axis is
BITSAT
Mathematics
Application of Derivatives
2020
BITSAT 2020
BITSAT Mathematics Question (2020) — Solution
Options
- A. x a - y b =1
- B. a x+b y=1
- C. a x-b y=1
- D. x a + y b =1
Answer
D. x a + y b =1
Step-by-step solution
y=b e^ -x / a meets the y -axis at (0, b). Again, d y d x =b e^ -x / a (- 1 a ) At (0, b), d y d x =b e^ 0 (- 1 a )=- b a Therefore, required tangent is y-b=- b a (x-0) or x a + y b =1
Related: Mathematics — Application of Derivatives · All PYQ Banks