Question

Dalam segitiga ABC diketahui cos A 1/2 akar 2 dan cos Beta 1/2 akar 3, cos (A-B) adalah

Answer 1

Cos A = ¹/₂ √2 maka sin A = ¹/₂√2
cos B = ¹/₂√3 maka sin B = ¹/₂

cos(A-B) = cos A cos B + sin A sin B
cos(A-B) = (¹/₂√2)(¹/₂√3) + (¹/₂√2)(¹/₂)
cos(A-B)= ¹/₄ √6 + ¹/₄√2

Answer 2

Dik:
cos A = 1/2 √2 = cos45
cos B = 1/2 √3 = cos30

Jwab:
cos(A-B) = cosAcosB+sinAsinB
cos(A-B) = cos45.cos30+sin45.sin30
cos(A-B) = 1/2√2.1/2√3+1/2√2.1/2
cos(A-B) = 1/4√6+1/4√2
cos(A-B) = 1/4(√6+√2)


Salam........ ^^