Mathematics

Mathematics

Problem

Within the interval 0<x<π0< x<\pi, how many distinct solutions does the equation sin⁡5x+sin⁡3x=0\sin 5x+\sin 3x=0 have? a) 44 b) 55 c) 33 d) 22
Intuitive explanation

This problem asks you to find where two sine waves cancel each other out. The key insight is to use the sum-to-product formula to combine sin⁡5x+sin⁡3x\sin 5x + \sin 3x into a single product, which equals zero when either factor is zero. This transforms a tricky trigonometric equation into two simpler ones you can solve separately, then count solutions carefully within the given interval.

Intuitive explanation

This problem asks you to find where two sine waves cancel each other out. The key insight is to use the sum-to-product formula to combine sin⁡5x+sin⁡3x\sin 5x + \sin 3x into a single product, which equals zero when either factor is zero. This transforms a tricky trigonometric equation into two simpler ones you can solve separately, then count solutions carefully within the given interval.

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