積分(cos x)/(3+sin平方x)dx
=積分1/(3+sin平方x)d(sinx)
=積分1/(3+x^2)dx
之後就是基本公式了,查查書把.
∫e^sin x/(e^sin x+e^cos x)dx在0~π/2上的積分
令x =π/2 - t,dx = - dt當x = 0,t =π/2,當x =π/2,t = 0L =∫(0-->π/2)e^sinx/(e^sinx + e^cosx)dx=∫(π/2-->0)e^sin(π/2 - t)/[e^sin(π/2 - t)+ e^cos(π/2 - t)]·- dt=∫(0-->π/2)e^cost/(e^…
∫sin^3(x)cos^2(x)dx=
把一個sin(x)拿出來
∫sin^3(x)cos^2(x)dx
=-∫sin^2(x)cos^2(x)d(cos(x))
=-∫(1-cos^2)cos^2(x)d(cos(x))
=-∫cos^2-cos^4(x)d(cos(x))
=-(cos^3(x))/3+(cos^5(x))/5+c
f(x)=2sin^2(π/4+x)+根號3(sin^2x+cos^2x) f(x)=2sin^2(π/4+x)+根號3(sin^2x-cos^2x)符號打錯了
f(x)=2sin^2(π/4+x)+√3(sin^2x-cos^2x)
=2sin^2(π/4+x)-√3cos2x
=1-cos(π/2+2x)+√3cos2x
=1+2(√3/2cos2x+1/2sin2x)
=1+2sin(π/3+2x)
是否存在α∈(-π/2,π/2),β∈(0,π),使等式sin(3π-α)=根號2 cos(π/2-β),根號3COS(-α)=-根號2sin 接上7π/2-β)同時成立?若存在,求出αβ的值,不存在,說明原因,
利用誘導公式化簡已知的兩個等式由sin(3π-α)=√2cos(π/2-β)得sinα=√2sinβ ①由√3COS(-α)=-√2sin(7π/2-β)得√3COSα=√2cosβ ②兩式平方相加得sin²α+3COS²α=2將余弦化成正弦得sin²α...
微積分,∫根號(x^2+a^2)dx 如題,求不定積分,∫根號(x^2+a^2)dx,
換元,令x=atanθ,把根號裡面化為asecθ,再用分部積分,結果是0.5a^2(secθtanθ+ln/secθ+tanθ/)+C,再把x=atanθ帶回去就可以了