Wednesday

February 22, 2017
Total # Posts: 394

**maths**

Does the parabola y = -3x^2 + 2x - 1 have a maximum or minimum value?

*September 1, 2013*

**maths**

Find the line that is perpendicular to y = -3/4 x + 2 and passes through (3,4).

*September 1, 2013*

**maths**

Sine and Cosine rule are both used in solving trigonometry problems.Give an example of when the cosine rule is more appliciable than the sine rule?

*September 1, 2013*

**maths**

Find the two stationary points on the curve when y = 2x/x^2 + 1

*September 1, 2013*

**maths**

A circle x^2 + y^ + 2x - 2y -1 = 0 expressed in the following form (x-h)^2 + (y-k)^2 = r^2 where h, k are the coordinates of the centre. How is r the radius given?

*September 1, 2013*

**maths**

A circle x^2 + y^ + 2x - 2y -1 = 0 expressed in the following form (x-h)^2 + (y-k)^2 = r^2 where h, k are the coordinates of the centre. How is r the radius given?

*September 1, 2013*

**Chemistry**

0.2 Faradays of electricity were passed through solutions of sulphuric acid. Calculate the volume of hydrogen evolved at s.t.p in sulphuric acid.

*August 24, 2013*

**Chemistry**

What would be the product formed for electrolysis of copper sulphate between the electrodes (a) Platinum (b) Copper and NaCl (aq) between (a)Platinum and (b) Copper electrodes?

*August 14, 2013*

**math**

what are the examples of exponetial notations

*August 12, 2013*

**maths**

Find the wind velocity if course 060 degree, airspeed 250km/h; track 040 degree, ground speed 260km/h.

*August 8, 2013*

**maths**

Find the course and ground speed if Track 150 degree, airspeed 400km/h; wind 040degree, 30km/h.

*August 8, 2013*

**maths**

Find the indicated term for (1-2x)^10, middle term.

*August 8, 2013*

**maths**

Find the ratio of the coefficients of the 4th and 6th terms in the expansion of (1 + 2x)^16

*August 8, 2013*

**chemistry**

This balance equation shows the burning of octane in air. 2C8H18 + 25O2 ----> 16CO2 + 18H2O. How many grams of carbondioxide will be produced when 1 mole of octane burns completely?

*August 8, 2013*

**maths**

Find the expansions of (1-x)^6 and (1+2x)^6 as far as the terms in x^3. Hence expand (1+x-2x^2)^6 up to the terms in x^3.

*August 8, 2013*

**maths**

The coefficient of x^2 is 69 in the expansion of (1-ax)^24, where a>0. Find the coefficient of x^3.

*August 8, 2013*

**maths**

Expand (1-x)^4. Hence find S if S = (1-x^3)^4 - 4(1-x^3)^3 + 6 (1-x^3)^2 - 4(1-x^3) + 1.

*August 6, 2013*

**maths**

In the expansion of (1-2x)^11 the coefficient of x^3 is k times the coefficient of x^2. Evaluate k.

*August 6, 2013*

**maths**

Expand (1-6x)^4 (1+2x)^7 in ascending powers of x up to and includeing the terms in x^3.

*August 6, 2013*

**maths**

In the expansion of (1-2x)^11 the coefficient of x^3 is k times the coefficient of x^2. Evaluate k.

*August 6, 2013*

**maths**

Expand (1+2x)^20 - (1-2x)^20) in ascending powers of x up to the term in x^5 and use this result to evaluate (1.02)^20 - (0.98)^20 to 3 significant figures.

*August 6, 2013*

**maths**

Obtain the binomial expansion of (2-x) (1+1/2x)^8 in ascending powers of x as far as the term in x^3. Use your result to estimate the value of 1.9 times (1.05)^8.

*August 6, 2013*

**Maths**

Pls help me to show that (1+root x)^5= 10 root x + 20x root x + 2x^2 ]oot x.

*August 5, 2013*

**chemistry**

1. In the following reactions, identify which reactants are the oxidizing agent and which are the reducing agents. a. 2S2O32- (aq) + I2 (s) ¨ 2I- (aq) + S4O62- (aq) b. NO3- (aq) + Zn (s) ¨ Zn2+ (aq) + NO2 (g)

*July 26, 2013*

**Chemistry**

A solution container was only label 0.005M. When phenolphthalene was added onto the solution, the color of the solution turned pink. After identifying the type of solution,it was later titrated with sodium carbonate. If the solution was sulphuric acid,determine the (a) [H...

*June 26, 2013*

**Chemistry**

Determine the [H+] when [OH-] is 2.0 times 10^-2 mole.dm-3.

*June 26, 2013*

**maths**

ABC is the segment of a circle with center O. This segment is enclosed in a rectangle APQC. Given that AC = 32 cm and AP = 8 cm, calculate; (a) The radius of the circle. (b) The angle AOC in both degrees and radians. (c) The area of the shaded region.

*June 20, 2013*

**Maths**

A surveyor measures the angle of elevation of the top of the mountain from a point (P) at sea level as 30 detre along a track which slopes uniformly uphill towards the mountain. From this point, which is 50 metre above sea level, he measures the angle of elevation as 40 degree...

*June 20, 2013*

**Chemistry**

Calculate the [H], [OH], pH and the pOH of this solution; 0.0025 M NaOH

*June 19, 2013*

**maths**

The position vector of the point A(3,4) relative to an origin O is a. (a) Express vector a or (OA) in terms of i and j. (b) Find the magnitude of a. (c) Find the unit vector in the direction of a.

*June 18, 2013*

**Maths**

ABC is the segment of a circle with center O. This segment is enclosed in a rectangle APQC. Given that AC=32cm and AP = 8 cm, calculate; (a) The radius of the circle. (b) The angle of AOC in both degrees and radians (c) The area of the shaded region.

*June 18, 2013*

**maths**

Expand (1-x)^4.Hence find S if S = (1-x^3)^4 - (1-x^3)^3 + 6(1-x^3)^2 - 4(1-x^3) + 1.

*June 18, 2013*

**maths**

Find two geometric progressions having: 54 as third term and 27/32 as ninth term.

*June 18, 2013*

**Maths**

Find the total amount required to pay off a loan of 16000 plus interest at the end of 8 years if the interest is compounded half-yearly and the rate is 14% p.a.

*June 18, 2013*

**Maths**

The third term of a sequence is 2(2/3) and the sixth term is 9. Find the first six terms when the sequence is; (a) arithmetic (b) geometric

*June 17, 2013*

**Maths**

Given the f (x) =2x^3 + ax^2 + bx - 9. (a)Find the value of a and b if f (x) has a factor x -3 but leaves a reminder of 8 when divided by x + 1. (b) Factorize f (x) completely and hence solve for x.

*June 17, 2013*

**maths**

If the nth term of a sequence is 3 x 2^n-1, Write down the first three terms.

*June 15, 2013*

**maths**

Find two geometric progression having: 2 as second term and 1458 as eight term,

*June 15, 2013*

**Chemistry**

One step of the Ostwald process for manufacturing nitric acid involves making nitrogen monoxide by oxidizing ammonia in the presence of a platinum catalyst: 4NH3 (g) + 502 (g)>> 4NO (g) + 6H2O (g). If the percentage yield is 80.3%, how many grams of NO can be produced ...

*June 10, 2013*

**Chemistry**

When 9.08 times 10^5 grams (one ton) of sodium chloride are electrolyzed in the commerical production of Chlorine, 5.24 times 10^5 grams of Chlorine are produced: 2 NaCl (aq) + 2 H2O (l) >>H2 (g) + Cl2 (g) + 2 NaOH (aq). Calculate the percentage yield.

*June 10, 2013*

**Chemistry**

When 9.08 times 10^5 grams (one ton) of sodium chloride are electrolyzed in the commerical production of Chlorine, 5.24 times 10^5 grams of Chlorine are produced: 2 NaCl (aq) + 2 H2O (l) >>H2 (g) + Cl2 (g) + 2 NaOH (aq). Calculate the percentage yield.

*June 10, 2013*

**MATHS - URGENT**

Write the expression in terms of sine only. 8(sin 2x − cos 2x)

*May 21, 2013*

**math**

tan(180-x)sin(360-x)cos90-x)cos(-x)/sin(x-180)cos(450+x)tan(180-x)

*May 19, 2013*

**7th math**

I just printed ine of them. 5 pages. Helpful thanks and I saved the other site.

*May 16, 2013*

**7th math**

Thanks too.

*May 16, 2013*

**7th math**

I'm having a hard time remembering these inequalities. DO you know of a site on the internet for me to practice?

*May 16, 2013*

**7th math**

I have no more than five books in my bag. I need to write an inequality for this, x<5 ?

*May 16, 2013*

**math**

Your favorite breakfast cereal contains a toy dinosaur in each box. There are four different dinosaur toys in the complete collection, and each one has an equal chance of being in each box. You want to figure out what the probability is that you will get more than one ...

*May 16, 2013*

**math**

2005 2006 2007 2008 Plant 1 20 4 25 10 Plant 2 25 5 5 48 Plant 3 20 8 20 32 Plant 4 43 10 10 47 Plant 5 40 11 15 48 A gardener recorded how many tomatoes 5 plants produced each year. Which year had the LARGEST interquartile range of tomatoes produced? A) 2005 B) 2006 C) 2007 D...

*May 16, 2013*

**Math**

Is that the answer or what I have x< =5.5 then i line on a number line half between 4 and 5 going left on a closed circle. Right?

*May 13, 2013*

**maths**

solve this equation. log (2x + 1) base 2 = -3

*May 8, 2013*

**maths**

Solve this logarithmic equation. 3 log 2 base x + log 18 base x = 2

*May 8, 2013*

**maths**

Solve this logarithmic equation. 3 log 2 base x + log 18 base x = 2

*May 8, 2013*

**maths**

Solve this equation. 3^2x - 3^x+2 = 3^x - 9

*May 8, 2013*

**maths**

Proof this identities. (a) sin x cot x = cos x

*May 8, 2013*

**maths**

Please I need help.Show full working out. (a) sin x cot x= cos x (b) (1 + tan theta)^2 + (1- tan theta)^2 = 2sec^2theta

*May 6, 2013*

**maths**

Please help me simplify this and show full working out. (a) (2x^3 divide 3y^4)^2 multiply (x divide 3y)^-2 (b) a-a^-1 divide a^2 - 1 (c) 3^a+2 times 9^2a+1 divide by 6^2 times 3^5a+3

*May 6, 2013*

**Maths**

Ship A is 18.5km from a port P on a beearing of 045 degree and ship B is 26.4km from point P on a bearing of 105 degree. Calculate the bearing of A from B and the distance AB.

*May 6, 2013*

**Maths**

Please help me.Iam stuck. Find all the possible values of theta between 0 degree and 360 degree for the following quadratic equation. State the quadrants in which each angle lie. 8 tan^2 theta + 2 tan theta=15

*May 6, 2013*

**Maths**

Please help me.Iam stuck. Find all the possible values of theta between 0 degree and 360 degree for the following quadratic equation. State the quadrants in which each angle lie. 8 tan^2 theta + 2 tan theta=15

*May 6, 2013*

**Maths**

AB is a 12 metre flagpole on top of a building. Given angle QPB=56 degree 37' and angle QPA=43 degree 19',find the distance of PB.

*April 30, 2013*

**Maths**

A and B are two balloons at the same height and 1000 metre apart. O is a ground observation position. Angle AOX is 45 degree 15' and angle BOX is 10 degree and 30'. Find the height of the balloons.

*April 29, 2013*

**Maths**

Find the area of the triangle with sides 8.6 cm, 9.1cm and 9.7cm. First find the size of one of the angles.

*April 29, 2013*

**Maths**

An aircraft which is maintaining a constant altitude of 1000 metre is travelling directly away from an observer. At a particular instant the angle of elevation is 52 degree and 12 seconds later the angle of elevation is 16 degree. Find the distance travelled in this time.

*April 29, 2013*

**Maths**

Please I need help.Iam stuck with this question.Using sine and cosine rule: A rocket launced vertically from L is observed from A. Soon after launch when at position M its angle of elevation is 25 degree. After it climbs 4000m from this position to N its angle of elevation is ...

*April 29, 2013*

**Maths**

Please help me. P and Q are two gun placements 1250m apart. T is a target. The angles TPQ and TQP are 73 degree 24' and 68 degree 5' respectively. Find the distance P to the target T.

*April 15, 2013*

**Maths**

Iam stuck.Please anyone help me. P and Q are two trees 490m apart beside a river. F is a flagpole on the other side of the river. If angle PQF=43 degree and angle QFP = 36 degree, Find the distance PF.

*April 15, 2013*

**Maths**

A and B are on the opposite side of tower.

*April 15, 2013*

**Maths**

A tower T is observed from two points A and B which are 240 metres apart. The angle TAB is found to be 57degree and the angle TBA is 78degree. Find the distance of the tower from A.

*April 15, 2013*

**HELP Physics**

The average rate at which energy is conducted outward through the ground surface in a certain region is 30.9 mW/m2, and the average thermal conductivity of the near-surface rocks is 3.11 W/m·K. Assuming a surface temperature of 9.48°C, find the temperature (in ...

*April 12, 2013*

**maths**

Iam stuck with this question.Please anyone help me. An airplane is flying at an altitude of 10,000m.The pilot sees two ships A and B.Ship A is due south of P and 22.5km away(in a direct line).Likewise ship B is due East and 40.8km from P. The height is 10km. Find the distance ...

*April 6, 2013*

**Maths**

Find all the values of theta between 0 degree and 360 degree, and state the quadrants in which they exist. (a)cos theta=-0.71 (b)tan theta=1.732

*April 5, 2013*

**Biology**

What are some of the treatments for coronary artery disease?

*April 5, 2013*

**Biology**

Explain what happens when a person with AB+ donates blood to a patient with A+ blood type?

*April 5, 2013*

**Biology**

Explain the role of white blood cells in the body's defense against foreign substances.

*April 5, 2013*

**maths**

From an observer 0, the angles of elevation to the bottom and top of the flag pole are 36 degree and 38 degree respectively. The base is 200m. Find the height of the flag pole.

*April 5, 2013*

**maths**

From an observer 0, the angles of elevation to the bottom and top of the flag pole are 36 degree and 38 degree respectively. The base is 200m. Find the height of the flag pole.

*April 5, 2013*

**maths**

Using the complementary angle ratio results,find the value of x for the following. (a) cos(x+35)degree=sin x degree (b) sec x degree=cosec(x+20)degree

*April 5, 2013*

**maths**

An airplane is flying at an altitude of 10,000m. The pilot sees two ships A and B. Ship A is due south of P and 22.5km away (in a direct line).Likewise ship B is due East and 40.8km from P. Find the distance between the two ships.

*April 5, 2013*

**Maths**

An aeroplane flies due north for 200 km and then turns due east and flies for a further distance of 325km. Find the bearing,to the nearest degree,of the aeroplane from its starting point.

*April 5, 2013*

**Maths**

Using the exact trigonometric ratios of 45 degree,30 degree and 60 degree,evaluate the following,leaving where necessary your answer in surd form. (a) 3 sin 30 degree-2 cos 60 degree (b)(tan 45 degree)(4 cos 60 degree-2 cos 60 degree)

*April 5, 2013*

**math**

c=Cost m=miles c=$3.00+(m*$2.00) If the number of miles=1 c=$3.00+(1*$2.00) c=$3.00+$2.00 c=$5.00

*March 28, 2013*

**6th grade Math**

A sample of 50 people in Harrisburg indicates that 10 people of them know the name of the mayor of their neighboring city. Out of 5, 500 Harrisburgh residents, how many would you expect to know the name of the mayor of the neighboring city?

*March 25, 2013*

**Art Ms. Sue please**

thye are right

*March 18, 2013*

**CHEM**

mass of C in sample = mass of C in CO2 mass of C in sample = (0.8635 g CO2 / 44 g/mol)(1 mol C / 1 mol CO2)(12 g/mol) = 0.2355 g mass of H in sample = mass of H in H2O mass of H in sample = (0.1767 g H2O / 18 g/mol)(2 mol H / 1 mol H2O)(1 g/mol) = 0.0196 g mass of O in sample...

*March 14, 2013*

**CHEM**

A 0.4647-g sample of a compound known to contain only carbon, hydrogen, and oxygen was burned in oxygen to yield 0.8635 g of CO2 and 0.1767 g of H2O. What is the empirical formula of the compound? i got C3H3O2 IS IT RIGHT?

*March 14, 2013*

**Chemistry**

WHATS THE GRAM OF H2O THEN?

*March 14, 2013*

**Chemistry**

oh nvmd yes the LR is O2

*March 14, 2013*

**chem**

COULD YOU PLS EXPLAIN IT TO ME.

*March 14, 2013*

**chem**

Consider the fermentation reaction of glucose: C6H12O6 ----) 2C2H5OH+2CO2 A 1.00-mol sample of C6H12O6 was placed in a vat with excess yeast. If 35.1 g of C2H5OH was obtained, what was the percent yield of C2H5OH?

*March 14, 2013*

**maths**

An observer on top of a building 66 metres high,finds the angle of elevation to the top of a taller building to be 34 degrees.The angle of depression to the foot of the same building is 51 degrees.If the buildings are on the same ground level find the height of the taller ...

*March 13, 2013*

**maths**

Find the area of an equilateral triangle whose base is 10 cm.

*March 12, 2013*

**Chemistry**

(1) Use the thermodynamic values to (a) deduce the enthalpy change of each reaction (b)state if the reaction is exothermic,or endothermic,and also how much energy is released or absorbed. For thi reactions; (1) NH4NO3 (s)------>N2 (g) + 2H2O (l) (2) 4Zn (s) + 9HNO3 (aq...

*March 12, 2013*

**Maths**

From a point on a lighthouse 76 metres above sea level,the angle of depression of a fishing boat 28 degrees.How far is the boat from the foot of the lighthouse?

*March 11, 2013*

**maths**

A surveyor finds two points A and B on a hillside to be 114.6 metres apart(measured along the line of sight) and finds the angle of elevation from A to B to be 21 degrees.On his plans these points must be shown at their horizontal distance apart.Find this distance.

*March 10, 2013*

**Maths**

The top of a T .V .tower casts a shadow 35 metres long when the angle of elevation of the sun 57 degree40 minutes.How high is the top of the tower?

*March 10, 2013*

**maths**

From an aircraft flying at 8000 metres above sea level the angle of depression of a ship is 36 degree15 minutes.How far is the ship from the plane in a straight line?

*March 10, 2013*

**maths**

A tourist viewing Sydney Harbour from a building 180 metres above sea level observes a ferry which is 850 metres from the base of the building.Find the angle of depression of his line of sight.

*March 10, 2013*

**maths**

Two walkers set off at the same time from a crossroad and walk along flat straight roads inclined to each other at 68 degrees.If they both walk at a speed of 6km/h,find their distance apart 10 minutes later.

*March 10, 2013*

**maths**

Two walkers set off at the same time from a crossroad and walk along flat straight roads inclined to each other at 68 degrees.If they both walk at a speed of 6km/h,find their distance apart 10 minutes later.

*March 10, 2013*