Question

If A= 45° then 2cos2 A-1
is equal to:
a) Cos 0°
b) Sin 0°
c) Sin 30°
d) Sin 60°​

Answer 1

hope this helps u

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cos 45 =√2/2

2 cos²a-1 = 2*(√2/2)²-1

                  = 2*$\frac{2}{4}$-1

                  = $\frac{2}{2}$ -1

                    = $\frac{2-2}{2}$

                      = $\frac{0}{2}$

                        = not defined = sinФ

Answer 2

Answer:

Step-by-step explanation:

hope this helps u

cos 45 =√2/2

2 cos²a-1 = 2*(√2/2)²-1

                 = 2*-1

                 =  -1

                   =  

                     =  

                       = not defined = sinФ