Hello, Macleef!
A silly mistake . . . don't kick yourself too hard.
The cosines don't cancel . . .Solve for
My Attempt:
. . . . no
We have: .
. .
Factor: .
Then: .
And: .
. . . .
Incorporate the use of the double angle formulas identities and other identities to solve for the following on
My Attempt:
0 and 180 and 360
Textbook Answers:
0 and 45 and 135 and 180 and 225 and 315 and 360
What am I doing wrong?
What did you do wrong?
From sinX /cosX = 2sinXcosX, how did you get sinX = 2sinX? What happened to the two cosX's?
You want me to solve the Problem?
After your sinX/cosX = 2sinXcosX,
Bring them all to the lefthand side,
sinX/cosX -2sinXcosX = 0
sinX(1/cosX -2cosX) = 0
sinX = 0
X = arcsin(0) = 0, 180, 360 degrees ---------***
1/cosX -2cosX = 0
Clear the fraction, multiply both sides by cosX,
1 -2cos^2(X) = 0
1 = 2cos^2(X)
1/2 = cos^2(X)
cosX = +,-sqrt(1/2)
cosX = +,-1/sqrt(2)
X = arccos(+,-1/sqrt(2))
X = 45, 135, 225, 315 degrees. ------***
Therefore, X = 0, 45, 135, 180, 225, 315, 360 degrees.