Question

Tolong kak no 11,12,13.
Makasih

Answer 1

no 11)

a + b = 10

a = 10 - b

pake aturan sinus aje..

a/sin A = b/sin B

10-b/sin 30° = b/sin 45°

10-b / 1/2 = b/(1/2√2)

20 - 2b = 2b/√2

20√2 - 2√2b = 2b

-2√2b - 2b = 20√2

b(-2√2 -2) = 20√2

b = 20√2 / (-2√2-2)

b = 20√2 / (-2√2 -2) x (-2√2 + 2)/(-2√2+2)

b = (-80+ 40√2)/(8-4)

b = (-80 + 40√2)/4

b = 10√2 -20

a = 10 - b = 10 - (10√2-20) = 30 - 10√2

no 12)

berarti

2a/sin 45 = 2/sin 30

2a/(√2/2) = 2/(1/2)

4a/√2= 4

4a = 4√2

a = 4√2/4

a = √2

no 13)

berarti

tan A = 3/a

tan 60 = 3/a

√3 = 3/a

a = 3/√3 = √3

jadi

3/sin A = a/sin B

3/√3 = √3/sin B

√3 = √3/sin B

sin B = 1

sudut B = 90°

cos B = cos 90° = 0

sin B +cos B = 1 + 0 = 1