4. Integration: Basic Trigonometric Forms

by M. Bourne


In this section, we obtain the following integral formulas by reversing the formulas for differentiation of trigonometric functions that we met earlier:

math expression

We now apply the power formula to integrate some examples.


Example 1: Integrate: math expression

Example 2: Integrate: math expression

Integral formulas for some other trigonometric functions: (These are obtained by just reversing the differentiation process).

math expression

Example 3: Integrate: math expression

NOTE: The above formulas were obtained by reversing the differentiation process.

Further Integrals

Now, if we want to find math expression, we note that

math expression

math expression

Similarly, it can be shown that

math expression

Hence, we can summarise that :

math expression


Example 4: Integrate: math expression

Example 5: Integrate: math expression

Example 6: Find the area under the curve of y = sin x from x = 0 to math expression.

Exercises

Integrate each of the given functions:

1. math expression

2. math expression

3. If the current in a certain electric circuit is i = 110 cos 377t, find the expression for the voltage across a 500-μF capacitor as a function of time. The initial voltage is zero. Show that the voltage across the capacitor is 90° out of phase with the current.

We need the following result from electronics, which gives the voltage across a capacitor, where C is the capacitance:

math expression

4. A force is given as a function of the distance from the origin as

math expression

Express the work done by this force as a function of x if W = 0 for x = 0.

Didn't find what you are looking for on this page? Try search:

Find your integral using Wolfram|Alpha!

This next search box allows you to enter your math problem and Mathematica solves it for you. (It's free!)

See how to enter math.

Online Algebra Solver

This algebra solver can solve a wide range of math problems. (Please be patient while it loads.)

Calculus Lessons on DVD

get MathTutorDVDs

Easy to understand calculus lessons on DVD. See samples before you commit.

More info: Calculus videos

Ready for a break?

shadow factory

Play a math game.

(Well, not really a math game, but each game was made using math...)

The IntMath Newsletter

Sign up for the free IntMath Newsletter. Get math study tips, information, news and updates each fortnight. Join thousands of satisfied students, teachers and parents!

Given name: * required

Family name:

email: * required

See the Interactive Mathematics spam guarantee.

Share IntMath!

Short URL for this Page

Save typing! You can use this URL to reach this page:

intmath.com/inttrig