Problem 64 of 7
Find exact trig value using identity: given sin theta=-3/7 and Quadrant IV, find cos theta.
Using a hint is okay. It just tells the trainer to give you a little more review.
Hidden until you reveal it.
simplify square roots and choose sign.
Hidden until you reveal it.
Result must be exact radical form with sign determined by quadrant.
Enter your answer
Your answer is equivalent to the expected form.
Walkthrough
Full solution stays hidden until you ask for it.
1. Apply sin^2+cos^2=1 to solve for the square of the target value.
2. Simplify the square root exactly.
3. Use quadrant information to choose the sign.
Use the worked steps, then substitute the final answer back into the original relationship to confirm it satisfies the prompt.
Decimal approximations when exact form is requested.