Table of Contents

## When should you use trig substitution?

As we saw in class, you can use trig substitution even when you don’t have square roots. In particular, if you have an integrand that looks like an expression inside the square roots shown in the above table, then you can use trig substitution. You should only do so if no other technique (e.g., u-substitution) works.

## How do you do trigonometry?

Starts here21:52Trigonometry For Beginners! – YouTubeYouTube

**What is Sohcahtoa trigonometry?**

“SOHCAHTOA” is a helpful mnemonic for remembering the definitions of the trigonometric functions sine, cosine, and tangent i.e., sine equals opposite over hypotenuse, cosine equals adjacent over hypotenuse, and tangent equals opposite over adjacent, (1) (2)

### What is the goal of trigonometric substitution?

The goal with trig substitution is to use substitution based on trig identities. We’re going to use substitution based on right triangles to make integration easier. So here, your goal might be to evaluate an integral, but you want to do that by finding an anti-derivative.

### What are trigonometric substitutions?

Trigonometric substitutions are a specific type of u u -substitutions and rely heavily upon techniques developed for those. They use the key relations sin^2x + cos^2x = 1 sin2 x+cos2 x = 1,

**How many possible solutions to trigonometric equations are there?**

Now, we know from solving trig equations, that there are in fact an infinite number of possible answers we could use. In fact, the more “correct” answer for the above work is, θ = 0 + 2 π n = 2 π n & θ = π 3 + 2 π n n = 0, ± 1, ± 2, ± 3, … θ = 0 + 2 π n = 2 π n & θ = π 3 + 2 π n n = 0, ± 1, ± 2, ± 3, …

#### How do you evaluate integrals with trigonometric identities?

mc-TY-intusingtrig-2009-1 Some integrals involving trigonometric functions can be evaluated by using the trigonometric identities. These allow the integrand to be written in an alternative form which may be more amenable to integration. On occasions a trigonometric substitution will enable an integral to be evaluated.

#### What is the difference between cosine and sine substitutions?

In particular, expressions involving square roots of quadratic functions may benefit from cosine or secant substitutions. Sine substitutions work in the same scenarios as cosine ones, and cosecant substitutions work in the same scenarios as secant ones. d = b^2 – 4ac d = b2 −4ac.