Please show your work. What have you tried and why do you think it wasn't working?
1.Cos2A+cos4A-cos3A=0, for 0≤A≤360
2.Show that Cos^-1(A)=Sin^-1 square root (1-A^2), (Inverse Trigonometric Function)
3.2cos3A-sin3A=Square root 5, for 0≤A≤360
4.Cos(A-∏/6) + sin (∏/6-A)=1, for 0≤A≤360
5.Tan3A=cot(∏/3-A), for 0≤A≤360
Thx for who helpING!!
1) Copy down the problem.
2) Examine a list of known identities for relationships that may prove useful.
This one can help...
cos(a+b) = cos(a)cos(b) - sin(a)sin(b)
3) You dive in and try something. Paralysis never solve problems.
4) You look for symmetries so you don't have to do the same work twice.
Hint: With a little effort, you can get the first one to:
If you convert this to look more familiar to the Algebra in you...
You should be able to solve this by factoring and the Quadratic Formula. (Don't forget your Rational Root Theorem!)