sinx+cosx

吕河饱4680已知sinx+cosx=1/5,( - π/2 -
吕玛视15050935742 ______[答案] sinx+cosx=1/5 两边平方得: 1+2sinxcosx=1/25 sinxcosx=-12/25 (3sin^2*x/2-2cosx/2sinx/2+cos^2*x/2)/tanx+(1/tanx) =(2sin²x/2-sinx+1)/1/sinxcosx =(1-cosx-sinx+1)*(-12/25) =(2-1/5)*(-12/25) =-108/125

吕河饱4680sinx+cosx等于什么求过程 -
吕玛视15050935742 ______ 根号2sin(45○十x)

吕河饱46801/(sin x+cos x) 的不定积分 -
吕玛视15050935742 ______[答案] ∫1/(sinx+cosx) dx =∫1/[√2·(sinxcosπ/4+sinπ/4·cosx)]dx =∫1/[√2·sin(x+π/4)] dx =√2/2 ∫csc(x+π/4) d(x+π/4) =√2/2 ln|csc(x+π/4)-cot(x+π/4)|+C

吕河饱4680几道辅助角公式题~sinx+cosx=?sinx - cosx=?sinx+根号3*cosx=?sinx - 根号3*cosx=?根号3*sinx+cosx=?根号3*sinx - cosx=? -
吕玛视15050935742 ______[答案] sinx+cosx =√2(sinxcosπ/4+cosxsinπ/4) =√2sin(x+π/4) sinx-cosx =√2(sinxcosπ/4-cosxsinπ/4) =√2sin(x-π/4) sinx+根号3*cosx =2(sinxcosπ/3+cosxsinπ/3) =2sin(x+π/3) sinx-根号3*cosx =2(sinxcosπ/3-cosxsinπ/3) =2sin(x-π/3) 根号3*sinx+cosx =2(sinxcos...

吕河饱4680y=sinx+cosx 化简~~! 急用 -
吕玛视15050935742 ______ y=√2sin(x+π/4)=√2cos(x-π/4)

吕河饱4680化简√3sinx+cosx.请写清解题过程. -
吕玛视15050935742 ______[答案] √3 sinx + cosx=2*(√3/2 sinx +½ cosx)=2*(sinx cos30º + sin30ºcosx) =2*sin(x+30º).

吕河饱4680函数f(x)=sinx+cosx有图.帮忙啦.在写出二次函数后不会了. -
吕玛视15050935742 ______ 解令t=sinx+cosx 即t=√2(√2/2sinx+√2/2cosx)=√2sin(x+π/4),即-√2≤t≤√2 又有t=sinx+cosx,平方得t²=1+2sinxcosx,即sinxcosx=(t²-1)/2 即原函数变为 y=t-√2(t²-1)/2=-√2/2t²+t+√2/2 (-√2≤t≤√2) 关于t的二次函数的对称轴t=-1/2*(-√2/2)=√2/2,开口向下 即当t=-√2时,y有最小值=-3√2/2 即选B.

吕河饱4680sinx+cosx=?
吕玛视15050935742 ______ sinx+cosx=根号2(根号2/2sinx+ 根号2/2cosx) 即系提取根号2 因为根号2/2=sin45=cos45 所以sinx+cosx=根号2sin(x+45)

吕河饱4680SINx+COSx=啥
吕玛视15050935742 ______ sinx+cosx = √2sin(x+45)

吕河饱4680sinx+cosx如何化简 -
吕玛视15050935742 ______ x∈[2kπ,2kπ π/2]时,f(x)=sinx cosx=√2sin(x π/4) x∈[2kπ π/2,(2k 1)π]时,f(x)=sinx-cosx=√2sin(x-π/4) x∈[(2k-1)π,2kπ-π/2]时,f(x)=-sinx-cosx=-√2sin(x π/4) x∈[2kπ-π/2,2kπ]时,f(x)=-sinx cosx=-√2sin(x-π/4)