I tend to use the natural log (ln).

## Three log rules – power, product, quotient

## Reviewing for RLS AATP Final

We did problems with trigonometry reviewing for the final.

The six trig functions are the ones in the two acronyms

SOHCAHTOA

CHOSHACAO

Sine, cosine, tangent, cosecant, secant, cotangent

One problem had numbers that looked like a 30 60 90 triangle.

A few times, the substitution of 1 = sin^2x + cos^2x

The trig functions can all be written in terms of sine and cosine and really, you could even write everything in terms of sine (but that wouldn’t be useful in this context).

It would help sometimes to be more comfortable with radians.

## Why you should not use the Law of Sines if you can use SOHCAHTOA instead

We went over some of the harder problems from previous tests. Some dealt with the Law of Sines and the Law of Cosines.

Others could simply use SOHCAHTOA. If you have a right triangle and one angle and a side (you could get the other angle beside the right angle easily) then you can use SOHCAHTOA.

That will be simpler and less steps and will reduce to the same thing as using the Law of Sines.

## Reviewing for RLS Final, Trig Functions

We reviewed for the final by mostly going over problems with trig functions.

SOHCAHTOA

CHOSHACAO

Understanding the reciprocal relationships was useful for a few problems.

Sometimes the double angle and half angle formulas were used.

Rewriting the functions in terms of sinx and cosx can be useful. As is knowing that sin^2x + cos^2x = 1 .

It would be helpful to memorize that

sin(0°) = 0

sin(90°) = 1

cos(0°) = 1

cos(90°) = 0

## Graphing Trig Functions

We worked mostly on problems with trigonometric functions.

A few involved graphing the functions. It can help quite a bit to know the shape of the graph in advance. But, if you do not, or even if you somewhat do, then you can use

SOHCAHTOA

CHOSHACAO

Also used some double angle formulas and saw how you can use the trig functions with sums for double angle formulas.

## Logarithm Properties, Tutoring at RLS

We worked on a problem with exponents and algebra.

Logarithms can be very useful for these problems.

There are three basic properties which are often used, two of them were used in this problem.

The logarithm of a quotient is the logarithm of the numerator minus the logarithm of the denominator.

The logarithm of a product is the logarithm of the first term plus the logarithm of the second term.

And the logarithm of something with an exponent brings the exponent in front of the expression as a multiplication.

## Tutoring Law of Cosines, RLS Friday Sheet

We mostly worked on problems with the Law of Cosines. Along with the Law of Sines, this equation can be helpful in figuring out sides and angles of triangles. The Law of Cosines is the Pythagorean Theorem generalized for triangles that are not right triangles.

Also looked at a Friday sheet. One problem with exponents and logarithms was the most involved.

Another involved asymptotes.

## Infinite sums, getting towards the idea of integration

Worked on problems related to the early ideas of calculus today.

The ideas today were closer to integration, finding an area using a summation of infinitely small rectangles using limits.

That meant finding the area of one rectangle and adding up all of them. So a base multiplied by a width.

The actual shape was a triangle and rectangle, but the technique becomes more useful for shapes which are not easy to calculate.

There were quite a few steps, so a single mistake could throw everything off.

## Algebra at CSUMB with trig identities- sine, cosine, tangent, cosecant, secant, cotangent

We mostly did problems with trig identities.

SOHCAHTOA

CHOSHACAO

Reduced a few radicals to a simpler form.

Talked about how the 30 60 90 triangle and 45 45 90 triangles have ratios that you should probably know in this context.