How do you express #cos(pi/ 3 ) * cos (( pi) / 6 ) # without using products of trigonometric functions?

1 Answer
Feb 26, 2017

The final answer is #sqrt3/4#

Explanation:

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For Trig functions, here is your best friend, the trig circle.
What you see here is for every section of the circle you have, there is a value for the cosine and sine for that value.

Therefore if you look at the line of #pi/3# in the first quadrant, the cosine of #cos(pi/3)#, is equal to #1/2#

When you look at the line #pi/6# in the first quadrant, #cos(pi/6)# is equal to #sqrt3/2#

Then the multiplication of #cos(pi/3)*cos(pi/6)# is just multiplying simple fractions.

#1/2*sqrt3/2=sqrt3/4#