No. 12 tolong jawab:)

Jawabannya:
tan^2 (a+b) + tan^2 (a+b)+2 tan (a+b). tan (a-b)
= sin^2 (1/2+1/2√2)+ sin^2 (1/2+1/1√2) + 2 sin
(1/2+1/2√2). sin (1/2.1/2√2)
= sin^2 (1/2+1/2√2+1/2+1/2√2)+ 2 sin (1/2+
1/2√2+1/2-1/2√2)
= sin^2 (2/4√2+2/4√2) + 2 sin (2/4√2+√2)
= sin^2. 1 + 2 sin (2/4√2+√2)
= sin^2. 1 + 2 sin 2/4√4
= sin 2 - √4. 1
= sin √2. 1
= sin √2 ------- B. √2

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