How to Solve Multivariable Calculus Problems with Two Variables: Tips and Tricks

[rmunoz]

Integral and Derivative Help!

Homework Statement

I have 3 problems that i am struggling to solve for the simple fact that there are two variables in each problem. I have no experience with multivariable calculus... i feel like I am missing something big because i have all the prerequisites for this physics course completed and with high grades yet this is our first hw... stuff we should be familiar with.
1. $$\int$$ 1/(d-x) dx

2. derivative of f(t)= sin($$\omega$$t -1)

3. $$\int$$ x/((x^2)+(L^2))^(3/2) dx

Homework Equations

The Attempt at a Solution

I've tried to solve 1 and 3 using trig substitution, partial fractions, integration by parts, u substitution but they all seem to lead to dead ends

 

[rock.freak667]

Assume 'd' and 'L' are constants. The first is a simple u-substitution. The second one, apply the chain rule.

 

[vela]

The third one is a simple substitution as well. You could also do it with a trig substitution.