<span>3sinx+4cosx=5
=> 3/5 sinx +4/5 cosx = 1
let cosA=3/5 => sinA=4/5
=> cosAsinx + sinAcosx = 1
=> sin(x+A) = 1
Now,
4sinx - 3cosx
= 5(4/5sinx - 3/5 cosx) [multipying numerator and denominator by 5]
= 5(sinAsinx - cosAcosx)
= -5{cos(x+A)} = -5[root{1-(sin(x+A)^2)}] = -5 x 0 = 0 Ans 0
TRICK: if asinx+bcosx is given then multiply numerator and denominator by root(a^2 +b^2)
this method is useful in many questions </span>
Do $15,000x.014x2
--
$15,000x.014=$210
$210x2=$420
Answer:
The length = 20
The width = 12
Explanation:
Let the Length of the garden be L and the Width W
Therefore the area of the garden = L*W
But we know that L = W + 8
Therefore the area of the garden can be expressed as W*(W + 8)
When the brackets are expanded this equals W^2 + 8W
The area of the recctangle which includes the path and garden will have a length of L + 8 (ie the length of the garden + 4 feet at the top and 4 feet at the bottom)
The width will be W + 8 (width of garden + 4 feet at the left and 4 feet at the right)
Therefore the area will be (W + 8)*(L +8)
Once again we know that L = W + 8
Therefore the area of the path/garden = (W +8)(W +8 +8)
=(W +8)(W +16)
=W^2 +24W + 128
We know that the path alone has an area of 320 square feet. Therefore if we subtract the area of the garden (W^2 + 8W) from the area of the path/garden the area left is the area of the path only
Therefore W^2 + 24W + 128 - (W^2 + 8W) = 320
W^2 + 24W + 128 - W^2 - 8W = 320
Simplify
16W + 128 = 320
Subtract 128 from both sides of the equation
16W = 192
divide both sides of the equation by 16
W = 12
As L = W + 8
L = 12 + 8 = 20
Answer:
Step-by-step explanation:
Answer:
9.5m
Step-by-step explanation:
646÷ 68 = 9.5 m
area ÷ height = base of triangle
