Question
Find the exact value of: sin60-cos60.
do I just type sin60-cos60 in my calculator?
= .37
do I just type sin60-cos60 in my calculator?
= .37
Answers
Reiny
no
if it says to find "exact" values, don't touch your calculator.
In this case you would be expected to know the ratio of sides of the standard 30,60,90 right-angled triangle
the sides across the angles 30,60,90 are
1,√3, and 2 in that order.
so sin 60 = √3/2 and cos 60 = 1/2
so sin60 - cos60 = √3/2 - 1/2
= (√3-1)/2
(of course it would be a good idea to test that answer on a calculator, it works!)
if it says to find "exact" values, don't touch your calculator.
In this case you would be expected to know the ratio of sides of the standard 30,60,90 right-angled triangle
the sides across the angles 30,60,90 are
1,√3, and 2 in that order.
so sin 60 = √3/2 and cos 60 = 1/2
so sin60 - cos60 = √3/2 - 1/2
= (√3-1)/2
(of course it would be a good idea to test that answer on a calculator, it works!)