45 degrees
pi/4
square root method
isolate x^2
√ both sides
square rooting use
+/-
solving quadratics by factoring
get =0
factor
set each =0
solve
trig identities work for
any value of x that is in the domain of the functions involved
every x value where the line y=1/2 intersects with the function y=sinx
is a solution to the equation sinx=1/2
another way of looking at it
pi/6 and 5pi/6 are solutions as well as every coterminal angle with pi/6 and 5pi/6
if a specific interval is given for solutions
you do not need to add the infinite number of periods
period of tangent
pi so pin
period of sin/cos
2pin
use both options with 2pin except for
tangent
multiple angle identities
use the horizontal shrink to find solutions
from [0, 2pi) there are
four solutions, two in each period so shrink the original solutions ands add the new period
solving equations with a calculator
use the inverse function to find the reference (first quadrant) angle, then apply that to the proper quadrants
you can check multiple angle identities by
substituting them into the original equation
in csc or sec
turn into recipricols
applying horizontal shrink
divide out coefficient on all erms and add pin number together
from Q1 to Q2
do pi - value given by calculator
cos memorize
43210
0, 30, 45, 60, 90
root and divide by 2
always use lcf
sin memorize
01234
0, 30, 45, 60, 90
root and divide by 2
always use lcf
tan memorize
0, 30, 45, 60, 90
0, always use √3/3, 1, √3, und.
quotient identities
tan and cot
quotient tan
sin/cos
quotient cot
cos/sin