∫(3x+1)/[(√4+x²;)] dx∫sin√x dx 麻煩給出這2題的詳細步驟

∫(3x+1)/[(√4+x²;)] dx∫sin√x dx 麻煩給出這2題的詳細步驟

∫(3x + 1)/√(4 + x²;)dx
令x = 2tanθ,dx = 2sec²;θdθ
=∫(6tanθ+ 1)/(2secθ)•;(2sec²;θ)dθ
=∫(6secθtanθ+ secθ)dθ
= 6secθ+ ln|secθ+ tanθ| + C
= 6 •;√(4 + x²;)/2 + ln|√(4 + x²;)/2 + x/2| + C
= 3√(4 + x²;)+ ln|x +√(4 + x²;)| + C
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∫sin√x dx
=∫sin√x •;(2√x)/(2√x)dx
= 2∫√xsin√x d(√x)
= -2∫√x d(cos√x)
= -2√xcos√x + 2∫cos√x d(√x)
= -2√xcos√x + 2sin√x + C