Math Assignment

SET 1

  1. The question mentions that for adhering to the diet the individual can allow 300 cal for the meal

We have –

1 ounce of milk – 20 cal

1 oz of cornflakes – 160 cal

Therefore, the individual can have either:

 300/20 = 15 ounces of milk

Or

300/160 = 1.875 oz of cornflakes

Say one ounce of milk = M

And 1 oz of cornflakes  = C

M as a function of C = M(C) = 15/1.875 = 8C

And

C as a function of M = C(M) = 1.875/15 = 0.125M

  1. We are given –

T = ar2+b

We know that the units on both sides of an equation should match.

T = temperature (say it is measured in Kelvins, K)

Therefore,

a)

ar2 = K

Since r is in km, a should be in:

a =K/ r2 i.e. temp/km2

 

And b will be measured in temp.

b)

Let us call the 2 set of values –

T1 = ar12+b

T2 = ar22+b

Now, r1 = 1260 km           r2 = 6260 km

          T1 = 4300 K                T2 = 1150 K

4300 = a*(1260)2 + b –(1)

1150 = a*(6260)2 + b –(2)

(1)    – (2):

4300-1150 = a*(12602-62602)

3150 = (1587600 – 39187600)*a

3150 = -37600000*a

I.e., a = -8.37766 x 10-5

 

Putting this in (1):

We get , b = 4300 – a*(1260)2

i.e. b = 4433.00000

We generally consider the parameter with most decimal places, which in this case is a.

Thus, we should have 5 significant figures after the decimal place for the answers.

                 = o-b

Let us call the 2 set of values –

1 = o-b

2 = o-b

We have-

[C1] = 1.1 x 10-4 mol dm-3

[C2] = 1.58 x 10-4 mol dm-3

               1 =0.016 Sm-1   2 = 0.02 Sm-1

                Substituting these in the two equations –

                0.016 = o -b-4 – (1)

                0.02 = o -b-4 – (2)

Solving these equations simultaneously-

(2)– (1):

0.02 – 0.016 =  – b (-4-4)

 i.e. b = -1.92149 Sm-1/ mol dm-3

Solving this in (1) –

 o  = -0.00415277 Sm-1

                       

  1. We have the following information from the problem statement-

  1. The equation varies sinusoidally. But since the range of a sin wave is from -1 to +1, this wave must be a scaled and shifted version of a sinusoid

Y = Asin(t+)

  1. Time period is = 1 minute i.e. 60 seconds T = 60 sec

i.e. f = 1/60 Hz

                 = 2 f = 2/T =

Therefore, we have:

 period

                The axis for this curve will be = (60+160)/2

= 110

I.e. A = Amplitude = min A – max A = 160-60 = 100

Thus, the formula for the sin wave is = 100sin(+)

5.

Let the 2 heights be h1 (height at low tide) and h2 (height at high tide)

Let the 2 times be t1 (time at low tide) and t2 (time at high tide)

We are given that-

Height h1 = 7 feet

Height h2 = 11 feet

Time t1 = 4 hours

Time t2 = 10 hours  (both counted in hours since midnight)

Since, the height of the tide is a function of time,

We have a general equation-

H = at+b

Now,

7 = 4a + b  – (1)

11 = 10a + b  -(2)

Now,

(2)    – (1):

4 = 6a

i.e. a = 4/6 = 2/3

Now, substitute a =2/3 in (1)-

7 = 4*2/3 + b

i.e. b =7 – 8/3 = 13/3

Thus, we have the final equation-

H = at+b

H = 2t/3 + 13/3

Or

3H = 2t + 13

SET 2

 

  1. g(t)= t2-3t

h(z) = 2z – 1

(a)    g(h(z)) = g(2z – 1)

= (2z-1)2-3(2z-1)

= 4z2-4z + 1-6z + 3

= 4z2-10z+4

(b)   h(g(t)) =  h(t2-3t)

= 2(t2-3t)-1

= 2t2-6t-1

(c)    h(h(t)) = h(2t-1)

= 2(2t-1) -1

=4t-2-1

= 4t-3

(d) g(g(z)) = g(z2-3z)

= (z2-3z)2– 3(z2-3z)

= z4-6z3+9z2-3z2+9z

= z4-6z3+6z2+9z

  1. Any number divided by zero is undefined.

Thus for all those denominators where F(x) = 0, the rules will not be valid for those values of x.

(a)    Denominator = x2 – 9

For x2 – 9 =0

x could be = -3 or +3

Therefore, for x= -3 and 3 , f(x) does not apply

(b)   g(x) =

Now,  = 0 for x=0

Thus for x = 0, g(x) is not valid

(c)    h(x) = / x

Now, x = 0 will make h(x) invalid

  1. (a) The straight line equation (slope intercept formula)states that-

è y-y1/x-x1 = y2-y1/x2-x1

The intercepts in this case are:

                                (2,-3) and (4,5)

                                  y+3/x-2 = 8/2

à (y+3)/(x-2) = 4

 y+3 = 4x – 8

i.e. y = 4x -11

m = 4 and c =-11

 (b) We know that equation of a line is-

  Line,  y = mx +c

Slope  m = -2

Y intercept c = 3

Therefore,

The equation of the given line is-

y = -2x + 3

(a)    cos x = -3/2

x = 5/6  + 2n radians where n

(b)   tan = 1

 = /4 +  n where n

(c)    sin x = -1/2

x  = -/6 + 2n where n

y = f(x) = 1 + 3sin(/4)

The +1 indicates, graph is shifted left by 1 unit.

A = 3 i.e. sin wave scaled by 3 times

x/4 indicates times period is quarter of a sin wave. I.e.  /2

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