Triangle that has the hypo as √(u^2 +1)

[Jbreezy]

Homework Statement

If I have a triangle that has the hypo as √(u^2 +1)
adj as 1 and oppo as u
I did an integral with trig sub. So I used

Homework Equations

u = tan(θ)

The Attempt at a Solution

At the end of my integral I ended up with an expression (1/4)sin(2θ)
When I substitute back into the integral for theta. I will get (1/2)(u/(sqrt(u^2 +1))
right? How does back sub work if you have 2(theta)

 

[vela]

Use $\sin 2\theta = 2 \sin \theta \cos \theta$. You need the trig functions in terms of $\theta$, not $2\theta$.

 

[Jbreezy]

Always like this? With double angle?

 

[vela]

Could you please use complete sentences? I'm not sure what you're asking.

 

[Jbreezy]

Nevermind thx