I am taking pre-cal at our local college and have my final on monday. The teacher gave us a study guide but I am having a few problems and need some help please. I am stuck on these two problems:
solve algebraically between [0,2pie]
2cosx +Sq. root2=0

other problem: solve for x
arccos x- arccot6/5=0

Can someone please show me how to work these. I am sure we went over it in class but I am lost. Thank you

2. #1:
Isolate cos(x):
$\displaystyle \begin{array}{rcl} 2\cos x + \sqrt{2} & = & 0 \\ 2\cos x & = & -\sqrt{2} \\ \cos x & = & -\frac{\sqrt{2}}{2}\end{array}$

Now I'm sure you've gone what values of x would work to solve the last line.

#2:
$\displaystyle \begin{array}{rcl} \arccos x - \text{arccot} \left(\frac{6}{5}\right) & = & 0 \\ \arccos x & = & \text{arccot} \left(\frac{6}{5}\right) \\ x & = & \cos \left[ \text{arccot} \left(\frac{6}{5}\right) \right] \end{array}$

In that last line, I basically took the cosine of both sides. You would need a calculator for this as I doubt you know the exact value of $\displaystyle \text{arccot} \left(\frac{6}{5}\right)$.

3. Thanks for the help. I will see what I can do.