From the "unit circle" cos(x)=0 when In terms of degrees: 90 and 270 degrees In terms of radians: (pi)/2 ...

Apr 15, 2015 · Simple cos 0 = 1. How do you use the ordered pairs on a unit circle to evaluate a trigonometric function of any angle?

Nov 6, 2014 · Best Answer. cos(0) = 1. So [cos(0)]^2 = [cos(0)] * [cos(0)] = 1 * 1 = 1 ....!!! CPhill Nov 6, 2014. Post New Answer

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In the second quadrant: sin and csc are positive, while cos, sec, tan, and cot are negative. tan(t) = 8. tan = opp/adj. Pick any numbers for opp/adj such that the quotient is 8.

Question 763289: Given cos 0=-4/5, and the angle 0 is in quadrant two, find the value for sin 0. Answer by lwsshak3(11628) ( Show Source ): You can put this solution on YOUR website!

You can put this solution on YOUR website! To prove: cos(20°) + cos(100°) +cos(140°) = 0 Write the angles in the first two terms in terms of their average, which is 60°, a special angle, and use a double angle identity on each: cos(20°) = cos(60°-40°) = cos(60°)cos(40°)+sin(60°)sin(40°) cos(100°) = cos(60°+40°) = cos(60°)cos(40°)-sin(60°)sin(40°) ----- SUM OF FIRST TWO …

The solutions of cos 2x = 0, in the interval 0 x 360. If we Let y=2x then we can rewrite cos 2x = 0 as cos y = 0. From the "unit circle" we know that this will be true when y = 90 deg and 270 deg. Now to find 'x': y=2x set y=90 90=2x 45 deg = x. set y=270 270=2x 135=x. solution: 90 …

Aug 12, 2015 · How do you find the general solutions for #cos 2x + cos x - 2 =0#? Trigonometry Trigonometric Identities and Equations Solving Trigonometric Equations 1 Answer

cos(π/2-θ) = sin θ & sin(π/2-θ) = cos θ or cos(90°-θ) = sin θ & sin(90°-θ) = cos θ. These are the complementary angle identities. Although the diagram shows the angle θ in the first quadrant, the same conclusion can be reached when θ lies in any quadrant, and so the complementary angle identities hold for all angles θ. 3.