Chương 6: CUNG VÀ GÓC LƯỢNG GIÁC. CÔNG THỨC LƯỢNG GIÁC
Các câu hỏi tương tự
Rút gọn các biểu thức sau:
1) \(A=2cosx+3cosx\left(\pi-x\right)-sin\left(\frac{7\pi}{2}-x\right)+tan\left(\frac{3\pi}{2}-x\right)\)
2) \(B=2sin\left(\frac{\pi}{2}+x\right)+sin\left(5\pi-x\right)+sin\left(\frac{3\pi}{2}+x\right)+cos\left(\frac{\pi}{2}+x\right)\)
sin\(\left(x+\frac{85\Pi}{2}\right)+cos\left(207\Pi+x\right)+sin^2\left(33\Pi+x\right)+sin^2\left(x-\frac{3\Pi}{2}\right)\)
Chứng minh rằng:
a) \(sin\left(a+b\right).sin\left(a-b\right)=sin^2a-sin^2b=cos^2b-cos^2a\)
b) \(4sin\left(x+\dfrac{\Pi}{3}\right).sin\left(x-\dfrac{\Pi}{3}\right)=4sin^2x-3\)
c) \(sin\left(x+\dfrac{\Pi}{4}\right)-sin\left(x-\dfrac{\Pi}{4}\right)=\sqrt{2}cosx\)
d) \(\dfrac{1}{sin10^0}-\dfrac{\sqrt{3}}{cos10^0}=4\)
Rút gọn:
C= \(sin^2\dfrac{\pi}{3}+sin^2\dfrac{5\pi}{6}+sin^2\dfrac{\pi}{9}+sin^2\dfrac{11\pi}{18}+sin^2\dfrac{13\pi}{18}+sin^2\dfrac{2\pi}{9}\)
D=\(cos\left(x-\dfrac{\pi}{3}\right).cos\left(x+\dfrac{\pi}{4}\right)+cos\left(x+\dfrac{\pi}{6}\right).cos\left(x+\dfrac{3\pi}{4}\right)\)
chứng minh các đẳng thức sau
a) \(\cos x\cos\left(\frac{\pi}{3}-x\right)\cos\left(\frac{\pi}{3}+x\right)=\frac{1}{4}\cos3x\)
b) \(\sin5x-2\sin x\left(\cos4x+\cos2x\right)=\sin x\)
\(\cos\left(5\Pi+x\right)+\sin\left(\frac{9\Pi}{2}-x\right)-\tan\left(\frac{3\Pi}{2}+x\right)\cot\left(\frac{3\Pi}{2}-x\right)\)
\(P=sin^2x+c\text{os}\left(\frac{\pi}{3}-x\right)c\text{os}\left(\frac{\pi}{3}+x\right)\)không phụ thuộc vào x
Chứng minh rằng: (Pls help me)
a, frac{1}{sin x}+cot xcotfrac{x}{2}
b, frac{1-cos x}{sin x}tanfrac{x}{2}
c,tanfrac{x}{2}left(frac{1}{cos x}+1right)tan x
d,frac{sin2a}{2cos aleft(1+cos aright)}tanfrac{a}{2}
e,cot x+tanfrac{x}{2}frac{1}{sin x}
f,3-4cos2x+cos4x8sin^4x
g,frac{1-cos x}{sin x}frac{sin x}{1+cos x}
h,sin x+cos xsqrt{2}sinleft(x+frac{pi}{4}right)
i,sin x-cos xsqrt{2}sinleft(x-frac{pi}{4}right)
l,cos x-sin xsqrt{2}cosleft(x+frac{pi}{4}right)
Đọc tiếp
Chứng minh rằng: (Pls help me)
a, \(\frac{1}{\sin x}+\cot x=\cot\frac{x}{2}\)
b, \(\frac{1-\cos x}{\sin x}=\tan\frac{x}{2}\)
c,\(\tan\frac{x}{2}\left(\frac{1}{\cos x}+1\right)=\tan x\)
d,\(\frac{\sin2a}{2\cos a\left(1+\cos a\right)}=\tan\frac{a}{2}\)
e,\(\cot x+\tan\frac{x}{2}=\frac{1}{\sin x}\)
f,\(3-4\cos2x+\cos4x=8\sin^4x\)
g,\(\frac{1-\cos x}{\sin x}=\frac{\sin x}{1+\cos x}\)
h,\(\sin x+\cos x=\sqrt{2}\sin\left(x+\frac{\pi}{4}\right)\)
i,\(\sin x-\cos x=\sqrt{2}\sin\left(x-\frac{\pi}{4}\right)\)
l,\(\cos x-\sin x=\sqrt{2}\cos\left(x+\frac{\pi}{4}\right)\)
29 tháng 5 2020 lúc 15:58
Thu gọn biểu thức
\(A=sin\left(\pi+x\right)-cos\left(\frac{\pi}{2}-x\right)+cot\left(2\pi-x\right)\)