Solving Trig Equations

1
ALWAYS work with 1st Quad then translate
CAST diagram
Exact Values
Solving Trig Equations
Example
Solve tanxo 1 0
tanxo -1
xo tan-1 (1)
xo 45o
sinxo 0.4
xo sin-1 (0.4)
Solution xo 180o - 45o 135o
xo 23.6o
xo 360o - 45o 315o
xo 180o - 23.6o 156.4o
2
Solving Trig Equations
Graphically what are we trying to solve
?
?
Example 5 Type 4 Solving the equation cos2x
1 in the range 0o to 360o
cos2 xo 1
cos xo 1
cos xo 1
xo 0o and 360o
cos xo -1
xo 180o