Jan 12, 2018 · Since Z>0 we know that Z could come from QI or QIV. We'll find hatZ, the reference angle for Z: cos (Z)=0.98 rarr hatZ=cos^ (-1) (0.98) For the QI angle, we have Z = cos^ (-1) (0.98) + 2pi*n, n in ZZ.

Aug 7, 2016 · cos3x = 1 8 cosx = 1 2 Trig table and unit circle give 2 arcs x that have same cos value. cosx = 1 2 --> x = ± π 3 The arc (− π 3) is the same as the arc 5π 3 --> (co-terminal) General answers: x = π 3 + 2kπ x = 5π 3 +2kπ

Feb 21, 2018 · arccos and cos−1 are equivalent and most calculators have cos−1 cos−1(− 0.41) = 1.99325038... or in degrees 114.20483... Make sure to round to whatever your assignment requires.

Dec 26, 2016 · Calculate cos^-1 (-0.8) in both Radians and Degrees by changing modes in your calculator and repeating the calculation. Change modes by pressing "setup" on the calculator, then press "angle unit" and change to your desired mode.

Jul 15, 2018 · The question can be read as .. "What angle has a cos value of 0.8217?" If you just need an angle in a right-angled triangle, then on a scientific calculator you would key in: shift/alt/ 2ndF cos−10.8217 = to get an angle of 34.7° However, if you want to include angles from 0° → 360° then we need to consider the sign and decide which quadrants we are working in. Cos is positive in the ...

Feb 28, 2018 · How do you write the equation cos α = 0.5 in the form of an inverse function?

Apr 20, 2016 · If a = cos−1(−1),cosa = − 1 If the range of a is specified as , say, [0,2π],a = π. The general solution is a = (2k +1)π,k = 0, ± 1, ± 2, ± 3...

Oct 25, 2016 · Transform the equation: 1 cosx = sinx cosx + 1 1 cosx = sinx + cosx cosx Simplify the equation, under condition (1) that cos x different to 0, meaning x different to π 2 and 3π 2 Next, solve the trig equation sin x + cos x = 1 Use trig identity: sinx + cosx = √2sin(x + π 4) = 1 sin(x + π 4) = 1 √2 = √2 2 The trig unit circle gives 2 solution arcs: …

Sep 3, 2016 · You key it in exactly as it is written. Use the shift/alt/2nd F key before the cos key, to use cos−1 This is not the same as 1 cos cos−1 is the way of finding which angle has a cos value of −0.3218 cos−1(− 0.3218) = 108.77° or cos−1(−0.3218) = 251.23°

Jun 14, 2017 · cos x = - 0.44. Calculator and unit circle give --> x = ± 116∘ +k360∘