e^xsin^2x的不定积分

来源:学生作业帮助网 编辑:作业帮 时间:2024/11/17 22:47:26
e^xsin^2x的不定积分
x)K(̋3x>Ɏާf=_iGMR>nI;zuV*QS64PHK*hiUh**$UhbQT@VNAMZSVM+@]lFCDQTjē8hDL4 g`i+^U Pxphb4D!Tuly7~ǩh3@=FP(k/.H̳7Q>

e^xsin^2x的不定积分
e^xsin^2x的不定积分

e^xsin^2x的不定积分
∫ (e^x)sin²x dx
= (1/2)∫ (e^x)(1 - cos2x) dx
= (1/2)∫ e^x dx - (1/2)∫ (e^x)cos2x dx
= (1/2)e^x - (1/2) • I
I = ∫ (e^x)cos2x = (1/2)∫ e^x d(sin2x)
= (1/2)(e^x)sin2x - (1/2)∫ (e^x)sin2x dx
= (1/2)(e^x)sin2x - (1/2)(-1/2)∫ e^x d(cos2x)
= (1/2)(e^x)sin2x + (1/4)(e^x)cos2x - (1/4)∫ (e^x)cos2x dx
(1 + 1/4) • I = (1/2)(e^x)sin2x + (1/4)(e^x)cos2x
I = (2/5)(e^x)sin2x + (1/5)(e^x)cos2x = (1/5)(e^x)(2sin2x +cos2x)
∴原式= (1/2)e^x - (1/2)(1/5)(e^x)(2sin2x +cos2x) + C
= (1/10)(5 - 2sin2x - cos2x)(e^x) + C