Question

The value of sinB cos (90° - B) + cos B sin (90°- B) is
(a) 0
(b) 1
(c) sinB cosB
(d) 2 sin2 B

need answer with step by step explanation ​

Answer 1

Correct option isB∵ sinAcosB+cosAsinB=sin(A+B)sinBcos(900−B)+cosBsin(900−B)=sin(B+900−B)=sin900=1

Answer 2

Answer:

(b)1

Step-by-step explanation:

$sinB cos(90 degree -B) +cosB sin(90 degree-B)\\=> sinB sinB + cosB cosB \\=> sin^{2}B + cos^{2}B \\=> 1$

because remember 90 degree - theta changes the ratio, and sin² +cos²=1.