Questions asked by Meilin H.

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• A trig question ask to proving an angle is 45 degrees?
  
• How to solve this equation? The topic is Radian Measure of Angle size.
  
• How to solve this for 0 ≤ x ≤ 2π ?
  
• If cosA=4/5. Find cos2A?
  
• If sinθ=2/3 and cosφ=1/4, where θ and φ are both acute, find cos(θ−φ)?
  
• Suppose that A is an acute angle and cosA=4/5. Find the exact value of sinA/2 ?
  
• A paddock on level ground is 2km long and 1km wide. If a farmer walks from one corner to the opposite corner along the fences in 40 minutes, how long will it take him walks across the diagonal?
  
• How many four-digit even numbers can be formed using the digits 3,4,7,8 if digits may be repeated?
  
• Find the number of possible arrangements of the letters in the word PENCILS if 'E' comes before 'I' ?
  
• Use compound-angle formulae to solve cos(x-30)=2cos(x+30), for 0<x<360 ?
  
• Solve 10cos x+13cos x/2=5 ?
  
• Solve 4sinx-cosx+3=0 ?
  
• Differentiate y=x^2+bx+c, and hence find b and c if: the parabola has y-intercept and has gradient -2 there?