Question

cos 1395.find d value?

Answer 1

what does d represent here?

Answer 2

-1/root2

Answer 3

hey shruti do u remember me... u wr asking me abt complex nos once?

Answer 4

cosine of any number repeats after every 360 degrees
therefore for getting the answer keep subtracting 360 till u r getting a +ve result
here 1395-360=1035
1035-360=675
675-360=315
315-360=-45
all the angles on the right of '=' sign have same values of trigo funtions
hence cos1395= cos(-45)
if u know cos(-x)=cos(x)
therefore the answer is 1/square root2