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How do you evaluate sine, cosine, tangent of #-pi/2# without using a calculator?

1 Answer

Jan 23, 2017

#"please look at animation below."#

Explanation:

#"first ,let us draw a unit circle. A unit circle is a circle with radius of 1."#

enter image source here

#" if "alpha=0, " then cosine=1, sine=0, tangent=0"#

enter image source here

#"if alpha="-pi/2 " then cosine=0, sine=-1, tangent="(-1)/0" undefined"#

enter image source here

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