- #1
doctordiddy
- 54
- 0
Homework Statement
evaluate the definite integral ∫(0 to 3) dx/sqrt(25+x^2)
Homework Equations
The Attempt at a Solution
I first used substitution and set x=5tanθ, and dx=5tanθsecθdθ
then i wrote the integral as 5∫ tanθsecθdθ/sqrt(25(1+tan^2(θ))
after some simplification i got
∫tanθsecθdθ/secθ = ∫tanθ =tanθsecθ
I then used θ=arctan(x/5) from the original x substitution and my final solution looked like this
tan(arctan(3/5))sec(arctan(3/5))-tan(arctan(0))sec(arctan(0))
It is incorrect, can anyone let me know where i might have done something incorrectly? Thanks