Posted by **Anonymous** on Thursday, November 22, 2007 at 5:35pm.

Solve the following equation for

0 less than and/or equal to "x" less than and/or equal to 360

--

cos^2x - 1 = sin^2x

--

Attempt:

cos^2x - 1 - sin^2x = 0

cos^2x - 1 - (1 - cos^2x) = 0

cos^2x - 1 - 1 + cos^2x = 0

2cos^2x - 2 = 0

(2cos^2x/2)= (-2/2)

cos^2x = -1

cosx = square root of -1

And I can't do anything with this now...what am I doing wrong?

--

Textbook answers:

0, 180, 360

--

- Math - Solving for Trig Equations -
**bobpursley**, Thursday, November 22, 2007 at 5:40pm
On the fourth/fifth line, you erred. When you add 2 to both sides, the right side is positive, not negative.

cos^2 x=1

cos x= +- 1

giving 1, 180,360

## Answer this Question

## Related Questions

- Math - Solving Trig Equations - Solve each equation for o is less than and/or ...
- Precalculs - I have no idea how to do these type of problems. -------Problem...
- algebra 2 and trig (math) - Find the value of x in the interval 0 is less than ...
- Trigonometry - Solve for the following equation to the nearest degree if needed ...
- Trigonometry - 4. Find the exact value for sin(x+y) if sinx=-4/5 and cos y = 15/...
- Precalc with Trig - What value(s) of theta (0 less than or equal to theta less ...
- Math - Solving Trig Equations - Solve each equation for 0 is less than and equal...
- Math/Trig - Solve: sin x - 2sin x cos x = 0 for 0 is less than or equal to x is ...
- Math - Solving Trig Equations - What am I doing wrong? Equation: sin2x = 2cos2x ...
- Math - Solving Trig Equations - Solve each equation on the interval: 0 is less ...

More Related Questions