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Show that cos3t equals 4cos cubed t - 3cos t?
cos(3t) = cos(2t + t) = cos(2t)*cos(t) - sin(2t)*sin(t) = [cos2(t) - sin2(t)]*cos(t) - 2*cos(t)*sin(t)*sin(t) = [cos2(t) - sin2(t)]*cos(t) - 2*cos(t)*sin2(t) then, since sin2(t) = 1 - cos2(t) = [2*cos2(t) - 1]*cos(t) - 2*cos(t)*[1 - cos2(t)] = 2*cos3(t) - cos(t) - 2*cos(t) + 2*cos3(t) = 4*cos3(t) - 3*cos(t)
What is cosine 850?
Cos of 850 degrees?850 deg = 130 + 360*2 = 130 degBy the graph of the cosine: cos(130) = -cos(50)and cos(50) is not a fraction of a root.cos(50) = 0.6427876...Therefore, cos(850) = -0.6427876...
How do you graph 1 divided by 4 cos?
0.25
Evaluate the following without a calculator and leave in radical form cos 90 sin 270?
First draw the graph. Label A S T C according to the order of plane. Draw a 90 degree angle. You see it's between All and Sin, so the answer is 0 Draw 270 degree angle. You see it's between Tan and Cos, so the answer is -1 And when you mix them together, 0 times -1 = 0.
What is this expression as the cosine of an angle cos30cos55 plus sin30sin55?
cos(30)cos(55)+sin(30)sin(55)=cos(30-55) = cos(-25)=cos(25) Note: cos(a)=cos(-a) for any angle 'a'. cos(a)cos(b)+sin(a)sin(b)=cos(a-b) for any 'a' and 'b'.
