Giải các pt sau:
1) \(\sqrt{x+3}+2x\sqrt{x+1}=2x+\sqrt{x^2+4x+3}\)
2) \(2\sqrt{x+3}=9x^2-x-4\)
3) \(1+\dfrac{2}{3}\sqrt{x-x^2}=\sqrt{x}+\sqrt{1-x}\)
4) \(\sqrt{x+3-4\sqrt{x-1}}+\sqrt{x+8-6\sqrt{x-1}}=1\)
5) \(\sqrt{x+2\sqrt{x-1}}+\sqrt{x-2\sqrt{x-1}}=\dfrac{x+3}{2}\)
⇔4x+1=-7
⇔4x=-8
⇔x=-2
quy dong se ra
Không dùng máy tính hãy tính:
A= Sin2100+Sin2200+Sin2450+Sin2700+Sin2800
B=Sin2420+Sin2430+Sin2440+Sin2450+Sin2460+Sin2470+Sin2490
C= tan350*tan400*tan450*tan500*tan550( dấu "*" là nhân nha)
D= cos2150-cos2250+cos2350-cos2450+cos2550-cos2650+cos2750
Giúp mình nha!