June 2019 archive

Week 17- precalc 11

This week in pre calc we reviewed the idea of trigonometry and then learned new things to add on to what we already knew.

So one of the things that we learned was the SIN LAW.

The sin law is

 

The lower case letters are the side length measurements and the upper case letters are the angles degrees.

Because the Sine Law works with the angles of triangles and the measurements of the triangles side then it’s useful in finding a missing angle or side.

how to use the sin law:

 

 

 

step 1: fill in what you know from the image

sinA/a = sinB/b = sinC/c

sinA/5 = Sin80/7 =sinC/c

and then u would take the two that has the most information/ what your looking for

in this case it would be sinA/5 = sin80/7

because were trying to find angle A

so we would next solve the equation

sinA = 5sin80/7

A=sin-1 (5sin80/7)

A= 44.7

and now you know what angle A is.

Week 16- pre calc 11

This week in PreCalc 11 we learned how to solve rational equations.

 

Rational equations are equations containing at least one fraction whose numerator or denominator is a variable.

There are two ways to solve rational equations, one of them is multiplying every term by each of the denominators or cross multiplication. Cross multiplication only works when there are two fractions and one is on each side of the equal sign (remember that a single number for example 4 is a fraction still because its over 1) I like multiplying the denominator better because multiplying by the denominator is a strategy that will work with every type of rational equation.

Example:

step 1: factor

step 2: multiply by the denominator

step 3: Non permissible values

step 4: solve

 

ex:  (there are no non- P values because there aren’t any variables in the denominator)