Question

Use the trigonometric subtraction formula for sine to verify this identity
sin(pi/2-x)=cosx
First of all what is the trigonometric subrtraction formula?
Second of all, how is this solved?

Answer 1

subtraction formula for sine:

sin(A-B)=sin A cos B - cos A sin B

so A=pi/2 and B=x in this case...

Answer 2

Okay so the left side then changes to sin pi/2 cos x - cos pi/2 sin x?
So the whole equation is then sin pi/2 cos x - cos pi/2 sin x=cos x

Answer 3

u got it...good job! :)

Answer 4

but now what?

Answer 5

you did a great job. you got the final answer.

Answer 6

thats all? really

Answer 7

subrtraction formula>> sin(A-B)=sin A cos B - cos A sin B

sin(pi/2-x) = sin pi/2 cos x - cos pi/2 sin x

as cos pi/2 = 0 and sin pi/2 = 1

expression becomes,
sin(pi/2-x) = (1)*cos x - 0*sin x

Answer 8

yes @cutiecomittee123 wat else u expecting? :P

Answer 9

Well then if thats it can either of you help me with another one?

Answer 10

and you have already done all that.

Answer 11

or a few other ones lol

Answer 12

how many r there?

Answer 13

i will let @princeharryyy help u :) good luck @cutiecomittee123

Answer 14

thanks man @superdavesuper

Answer 15

u gave her the solution.

Answer 16

Okay derive the trigonometric addition formula for sine
sin(a+b)=sinacosb+cosasinb

Answer 17

there are a few maybe 3 questions besides the one I just asked

Answer 18

are you sure that you have to derive it, coz it's lengthy.