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Hitman42 [59]
3 years ago
8

Prove the identity sin3x=3sinx-4sin³x

Mathematics
1 answer:
alexandr1967 [171]3 years ago
7 0

Hi

we know that sin(A+B)=Sin(A)Cos(B)-Cos(A) Sin (B)

cos(2x)=1-2sin²(x)

sin(2x)=2sin(x)cos(x)

Exp:- Sin(3x)=Sin(x+2x)

Sin(x)cos(2x)+cos(x)sin(2x)

sin(x){1-2sin²(x)}+2cos²(x)sin(x)

sin(x)-2sin³(x)+2sin(x){1-sin²(x)}

sin(x)-2sin³(x)+2sin(x)-2sin³(x)

3sin(x)-4sin³(x)

Hope it helps....

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Help idk how to do this ASAP please
Sergio039 [100]

Answer:

The area of ∆DEF = 4.5in²

Step-by-step explanation:

From the above diagram,

∆BAC ~∆DEF

It is important to note that if two triangles are similar, the ratio of their areas is equal or equivalent to the ratio of the areas of their sides

This means for the above question, that

We have the bigger triangle = ∆BAC has a side of 4 in and Area = 8 in²

The small triangle has a side of 3in

Finding the scale factor k = ratio of the sides of both Triangles

k = 4/3

k² = (4/3)²

k² = 16/9

Hence,

Area of ∆BAC/ Area of ∆DEF = 16/9

8in²/Area of ∆DEF = 16/9

We cross Multiply

8 in² × 9 = Area of ∆DEF × 16

Divide both sides by 16

Area of ∆DEF = 72/16

= 4.5in²

Therefore, the Area of ∆DEF rounded to the nearest tenth = 4.5in²

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3 years ago
In how many ways can a set of two nonnegative integers less than 100 be chosen?
hichkok12 [17]

Answer: 4950

Step-by-step explanation:

The number of possible combinations of n things taken r at a time is given by :-

C(n,r)=\dfrac{n!}{r!(n-r)!}

Total nonnegative integers less than 100 ={0,1,2,... ,99} = 100

So, the number of combinations of choosing 2 out of them = C(100,2)=\dfrac{100!}{2!98!}=\dfrac{100\times99\times98!}{2\times98!}\\\\=\dfrac{100\times99}{2}\\\\=50\times 99\\\\=4950

So, the number of ways to choose a set of two nonnegative integers less than 100 = 4950

5 0
3 years ago
A triangle has side lengths of (2b+c)(2b+c) centimeters, (7b+4d)(7b+4d) centimeters, and (6d+2c)(6d+2c) centimeters. Which expre
Gnoma [55]

Answer:

(9b + 3c + 10d)cm

Step-by-step explanation:

Given the sides of a triangle expressed as (2b+c), (7b + 4d) and (6d+2c). The perimeter of the triangle is the sum of all the sides of the triangles.

Perimeter of the triangle = 2b+c + 7b+4d + 6d+2c

Perimeter of the triangle = 2b + 7b + c + 2c + 4d + 6d

Perimeter of the triangle = 9b + 3c + 10d

Hence the perimeter of the triangle is (9b + 3c + 10d)cm

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3 years ago
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Tasya [4]

Answer:

BaseBall hats: 40%

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Step-by-step explanation:

10/25= baseball hats or: 10*4: 25*4: 40/100: 40%

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