Question

Find A and B if sin (A + 2B)and cos (A + 4B) = 0, where A and B
are acute angles.
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Answer 1

Answer:

A= -90 and B=45

Step-by-step explanation:

if sin(A+2B)= 0

then ,

sin(A+2B)=sin0

A+2B=0. ......1

and now

cos(A+4B)=0

then

cos(A+4B)=cos90

A+4B=90. .....2

now from eqe. 1and 2

2B=90

B=45

then A= -90

Answer 2

Answer:

Step-by-step explanation:

$sin(A+2B)=0\\\\cos(A+4B)=0\\\\sin(A+2B)=sin0\\\\A+2B=0  .....(i)\\\\cos(A+4B)=cos90\\\\A+4B=90....(ii)\\\\(i)-(ii)\\\\2B = 90\\B=45$

value of B put in eq (i)

then A + 45*2 = 0

        A  = -90