Answer:
see explanation
Step-by-step explanation:
Using the double angle identity for sine
sin2x = 2sinxcosx
Consider left side
cos20°cos40°cos80°
= (2sin20°cos20°)cos40°cos80°
= (2sin40°cos40°)cos80°
= (sin80°cos80° )
= (2sin80°cos80° )
= . sin160°
= . sin(180 - 20)°
= . sin20°
= = right side , thus proven
Answer:
The dimensions of the newly formed rectangle is length is 41 cm and width is 9 cm.
Step-by-step explanation:
Given,
A 1 meter steel rod is bent into a rectangle.
That means the perimeter of the rectangle is 1 meter.
So, Perimeter =
Let the width of the rectangle be 'x'.
Now According to question, length exceeds quadruple its width by 5 cm.
Hence framing the above sentence in equation form, we get;
Now we use the formula of perimeter of rectangle,
On substituting the values, we get;
Now, we substitute the value of x to get the value of length;
Thus, Width=9 cm Length=41 cm
Hence the dimensions of the newly formed rectangle is length is 41 cm and width is 9 cm.