BITSAT 2024 · Paper 1 · Mathematics · Indefinite Integration
The value of ∫ e^ θ ( θ- θ) d θ is
The value of ∫etanθ(secθ−sinθ)dθ is
Options
Aetanθsecθ+c
Betanθsinθ+c
Cetanθ(secθ+sinθ)+c
Detanθcosθ+c
Correct answer
D. etanθcosθ+c
Step-by-step solution
Let I=∫etanθ(secθ−sinθ)dθ
Put tanθ=t⇒sec2θdθ=dt⇒dθ=1+t2dt⇒I=∫et(1+t2−1+t2t)1+t2dt=∫et(1+t21−(1+t2)3/2t)dt
Integrating first part by parts we have,
=1+t21et+∫(1+t2)3/2t⋅etdt−∫(1+t2)3/2tetdt+c=1+t2et+c=etanθcosθ+c