Simplify each expression. 5 c) 1-2sin^2 3π/8 I got 1-2sin^2 67.5 Cos2Θ= 1-2sin^2 67.5 I dont know exactly what to do from there...
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Originally Posted by Skoz Simplify each expression. 5 c) 1-2sin^2 3π/8 I got 1-2sin^2 67.5 Cos2Θ= 1-2sin^2 67.5 I dont know exactly what to do from there... Leave it in terms of otherwise you will never solve it (because ) To solve use the angle difference formula: Spoiler: Exact values of sin and cos at the two above values:
where does the 3pi/4 come from? and how does cos (3pi/4)= (pi-pi/4) where did the 3 go?
Originally Posted by Skoz where does the 3pi/4 come from? and how does cos (3pi/4)= (pi-pi/4) where did the 3 go? I used the double angle formula for cos: Therefore comes from simplifying the cos term The 3 is turned into a 4-1. If you imagine then we see that I used and because their exact values are known
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