Answer:
Choice B. sin(B)=cos(90-B)
Step-by-step explanation:
That cofunction identity is the one you looking for...choice B.
If you aren't convinced or don't know that identity, then maybe this will help:
90-B is actually the same thing as saying A for this right triangle since A+B=90.
So choice B basically says sin(B)=cos(A)
Well let's find both sin(B) and cos(A)
sin(B)=b/c
cos(A)=b/c
Those are the same ratios!
So they are equal!
Answer:
option B
Step-by-step explanation:
from the given options
a) sin (B) = sin (A)
b) sin (B ) = cos (90° - B)
cos (90° - B ) = Sin B
c) cos (B ) = sin(180° - B)
sin(180° - B) = sin (B)
d) cos (B) = cos(A)
so, we can clearly see from the above solution that option B is correct.
As 90° - B is in first quadrant and in first quadrant sign of cos dose not change and 90 is multiple of odd so 'cos' changes to 'sin'
