Question

trig identities

Answer 1

\[\sin (\pi/2 \pm \theta) = \pm \cos(\theta)\] right? my book says minusplus cos(theta)

Answer 2

@ganeshie8 @ajprincess

Answer 3

can someone just tell me if i am right or wrong..

Answer 4

it depends on the theta .
when pi/2+theta then sin is in second quadrant so it should be positive
when pi/2 - theta then it is in fourth quadratic then should be negative.

Answer 5

but does it matter wether its plusminus or minus plus in front of cos(theta)?

Answer 6

i think when Phi/2-theta, it's still in the first quadrant... so it be positive

Answer 7

ok thx :)

Answer 8

@RadEn correct !!!