Here are the solutions to the questions from your image:
Probability Question:
There are 11 blue balls and 7 red balls, making a total of 11+7=18 balls. We are picking two balls without replacement.
Step 1: Calculate the probability of picking a blue ball first, then a red ball second.
P(1stBlue)=1811
After picking one blue ball, there are 17 balls left, with 7 red balls remaining.
P(2ndRed∣1stBlue)=177
P(BluethenRed)=1811×177=30677
Step 2: Calculate the probability of picking a red ball first, then a blue ball second.
P(1stRed)=187
After picking one red ball, there are 17 balls left, with 11 blue balls remaining.
P(2ndBlue∣1stRed)=1711
P(RedthenBlue)=187×1711=30677
Step 3: Add the probabilities of these two mutually exclusive events to find the total probability of picking balls of different colours.
P(DifferentColours)=P(BluethenRed)+P(RedthenBlue)
P(DifferentColours)=30677+30677=306154
Step 4: Simplify the fraction.
306154=15377
The probability that both balls are of different colours is 15377.
Implicit Differentiation Proof:
Given the equation x2+2xy+3y2=1.
We need to prove that (x+3y)3dx2d2y+2=0.
Step 1: Differentiate the given equation implicitly with respect to x.
dxd(x2)+dxd(2xy)+dxd(3y2)=dxd(1)
Using the product rule for 2xy and the chain rule for 3y2:
2x+(2⋅y+2x⋅dxdy)+(3⋅2y⋅dxdy)=0
2x+2y+2xdxdy+6ydxdy=0
Step 2: Solve for dxdy.
(2x+6y)dxdy=−2x−2y
dxdy=2x+6y−2x−2y=2(x+3y)−2(x+y)
dxdy=−x+3yx+y
Step 3: Differentiate dxdy again with respect to x using the quotient rule.
Let u=−(x+y) and v=x+3y.
Then dxdu=−(1+dxdy) and dxdv=1+3dxdy.
The quotient rule is dx2d2y=v2vdxdu−udxdv.
dx2d2y=(x+3y)2(x+3y)(−(1+dxdy))−(−(x+y))(1+3dxdy)
dx2d2y=(x+3y)2−(x+3y)(1+dxdy)+(x+y)(1+3dxdy)
Step 4: Substitute dxdy=−x+3yx+y into the numerator.
Numerator:
−(x+3y)(1−x+3yx+y)+(x+y)(1−3x+3yx+y)
=−(x+3y)(x+3yx+3y−(x+y))+(x+y)(x+3yx+3y−3(x+y))
=−(x+3y)(x+3y2y)+(x+y)(x+3yx+3y−3x−3y)
=−2y+(x+y)(x+3y−2x)
=x+3y−2y(x+3y)−2x(x+y)
=x+3y−2xy−6y2−2x2−2xy
=x+3y−2x2−4xy−6y2
=x+3y−2(x2+2xy+3y2)
From the original equation, we know that x2+2xy+3y2=1.
So, the numerator simplifies to x+3y−2(1)=x+3y−2.
Step 5: Substitute the simplified numerator back into the expression for dx2d2y and rearrange.
dx2d2y=(x+3y)2x+3y−2
dx2d2y=(x+3y)3−2
Multiply both sides by (x+3y)3:
(x+3y)3dx2d2y=−2
Add 2 to both sides:
(x+3y)3dx2d2y+2=0
This proves the statement.
Trigonometry Question:
The question asks to "find the value of cosy−siny4tany" given 0∘≤y≤90∘. This question is incomplete as there is no additional information or equation provided to determine a specific value for y or the expression. Without more context, the expression cannot be simplified to a numerical value.
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