Questions asked by TK02

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• `1/costheta+3sinthetatantheta+4=0` can be expressed as `3cos^2theta - 4costheta -4=0`. Hence solve the equation `1/costheta+3sinthetatantheta+4=0` for `0<=theta<=360` ?
  
• The coefficients of `x^2` and `x^3` in the expansion of `(3-2x)^6` are *a* and *b* respectively. Find the values of `a/b` ?
  
• Which would contain 9.03 × 10^23 oxygen atoms? A) 0.25 mol aluminium oxide B) 0.75 mol sulfur dioxide C) 1.5 mol sulfur trioxide D) 3.0 mol water
  
• Which reaction involves a decrease in the bond angle at a carbon atom? A. bromoethane refluxed with ethanolic sodium hydroxide B. complete combustion of methane in air C. ethanol heated with conc. H2SO4 D. polymerisation of ethene
  
• In which hydride is the H-X-H bond angle the smallest?
  
• A curve has equation `y=k/x`. Given that the gradient of the curve is `-3` when `x=2`. Find the value of constant `k.`?
  
• A curve is such that `dy/dx=4/sqrt((6-2x))` and `P(1,8)` is a point on the curve. 1. The normal to the curve at the point `P` meets the coordinate axes at `Q` and at `R`. Find the coordinates of the mid-point of `QR.` 2. Find the equation of the curve?
  
• Haemoglobin binds oxygen in the lungs to form oxyhaemoglobin. Describe what causes oxygen to be released from the oxyhaemoglobin as blood flows through respiring tissues?
  
• Describe the role of the ribosome in translation?
  
• Describe the changes that occur during prophase in an animal cell?
  
• Describe the role of ribosomes in protein synthesis?
  
• Describe the role played by tRNA in *translation* and in *polypeptide synthesis*?
  
• Prove the identity `(1/sinx - 1/tanx)^2 -= (1-cosx)/(1+cosx).` ?
  
• Relative to an origin O, the position vectors of points A, B and C are given by `vec(OA)= 0uli + 2ulj + (-3)ulk` `vec(OB)= 2uli + 5ulj + (-2)ulk` `vec(OC)= 3uli + pulj + qulk` (i) In the case where ABC is a straight line, find the values of *p* and *q?
  
• Particles *P* and *Q* move on a line of greatest slope of a smooth inclined plane. *P* is released from rest at a point *O* on the line and 2s later passes through the point *A* with speed `3.5ms^-1`. (i) Find the acceleration of *P* and the angle?
  
• 1-bromopropane is a minor product of a reaction. Explain why 2-bromopropane is the major product of that reaction?
  
• Explain why 2-bromomethylpropane is the major product of a reaction while only relatively small amounts of 1-bromomethylpropane are produced?
  
• (i) Show that the value of **k** is 0.1. (ii) Find an expression for the displacement of the particle from the origin in terms of t?
  
• Differentiate `(sqrt(x) + 1 )^2/ x` with respect to `X.`?
  
• Given that D is a point lying on the line through B and C find 2 possible vectors of point D?
  
• Find the value of *a* for which there is no term independent of *x* in the expansion of `(1 + ax^2)(2/x - 3x)^6`?
  
• Mechanic help?
  
• Mechanics, help?
  
• Solve the question ?
  
• Functions, Help?
  
• Quadratics and functions, Help please ?
  
• Identities, Please Help??
  
• Please help Q1?
  
• Determine whether `3x^3 - 6x^2+5x-12` is an increasing function, a decreasing function or neither?
  
• Find the values of *k* for which `vec(AB)` is a unit vector.?
  
• State the smallest value of k for which g has an inverse?
  
• In the case where OAB is a straight line, state the value of p and find the unit vector in the direction of `vec(OA)`?
  
• Differentiate `y = 9/(2x + 3`?
  
• Vector question?
  
• Help with this question?
  
• Chlorine, Bromine and Iodine all react with hydrogen. (i) State the trend in the reactivities of the halogens with hydrogen. (ii) Explain the trend in terms of bond energies.?
  
• Mechanics help?
  
• How many esters with the molecular formula `C_5H_10O_2` can be made by reacting a primary alcohol with a carboxylic acid? A. 4 B. 5 C. 6 D. 8?
  
• Substance M is refluxed with aqueous sodium hydroxide. One of the products of this reaction reacts with alkaline aqueous iodine to give a pale yellow precipitate. Which compounds could be substance M?
  
• Find the exact value of `int_0^(1/2pi)x^2sin2x dx`?
  
• Express `f(x) = (3x)/ [(1 +x)(1+2x^2)]` in partial fractions?