Given:
limx→0 [ sin(ax) / (bx) + sin(bx) / (ax) ]
where a ≠ 0, b ≠ 0 and a + b ≠ 0
Step 1: Split the limit
limx→0 [ sin(ax)/(bx) + sin(bx)/(ax) ]
= limx→0 sin(ax)/(bx) + limx→0 sin(bx)/(ax)
Step 2: Simplify each term
sin(ax)/(bx) = (a/b) · [ sin(ax)/(ax) ]
sin(bx)/(ax) = (b/a) · [ sin(bx)/(bx) ]
Step 3: Apply standard limits
limθ→0 sinθ/θ = 1
So,
limx→0 sin(ax)/(ax) = 1
limx→0 sin(bx)/(bx) = 1
Step 4: Evaluate the limit
limx→0 [ sin(ax)/(bx) + sin(bx)/(ax) ]
= (a/b) + (b/a)
= (a2 + b2) / ab
Final Answer:
limx→0 [ sin(ax)/(bx) + sin(bx)/(ax) ] = (a2 + b2) / ab