KVPY2015MathematicsDefinite Integration
Let x >0 be a fixed real number. Then the integral ₀^ e^ -t |x-t| d t is equal to.
Options
- Ax+2 e^ -x -1
- Bx-2 e^ -x +1
- Cx+2 e^ -x +1
- D-x-2 e^ -x +1
Correct answer
A. x+2 e^ -x -1
Step-by-step solution
₀^ x e ^ -t |( x - t )| dt = ₀^ x e ₁₁⁻¹( x - t ) dt + _ x ^ x e ₁₁⁻¹( t - x ) dt -( x - t ) e ^ -t -(-1) e ^ - t ₀^ x - -( x - t ) e ^ - t + e ^ -t )_ x = x +2 e ^ -x -1