Questions asked by Kody D.

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• How to solve #8sin^2x+4cos^2x=7# for 0≤x≤2π?
  
• How to Solve #5-4cosx=4sin^2x# for #-90°<=x<=90°# ?
  
• Use expansion of #sin(A+B)# to prove #sin(x+pi/2)=cosx# ?
  
• Solve #sinxcos##pi/6+cosxsinx##pi/6=1/sqrt2# for #0<=x,=2pi# ?
  
• Determine the values of #a# and #b#?
  
• The sound level at the side of a busy road to be 91 dB when eight trucks are passing at the same time. If the trucks are each contributing about the same level of sound, what would the sound level be if only one truck passed at one time?
  
• The Curve #y=ax^3+bx^2+cx+5# passes through the point #P (-1,4)# and at the point #P# the first and second derivatives of the curve are #8# and #-24# respectively. Find the values of the constants #a,b and c#?
  
• A stone is dropped from a helicopter hovering at a constant height of 490m. How long before the stone reaches the ground?
  
• A stone is dropped from a helicopter which is rising steadily at #19.6ms^-1#. If the stone is released when the helicopter is at an altitude of #24.5m#, how long does it take for the stone to reach the ground?
  
• A stone is dropped out of a balloon which is descending at #14.7 ms^-1# when the balloon is at an altitude of #49 m#. How long before the stone hits the ground?
  
• How to solve Motion Question?
  
• How to solve Motion Question?
  
• What is the oxidation number of iron in goethite?