Answer:
x=πn, n∈Z
Step-by-step explanation:
if sin²2x=1-cos²2x, then
1-cos²2x-2cos2x+2=0; ⇒ cos²2x+2cos2x-3=0; ⇔ (cos2x+3)(cos2x-1)=0;

Answer:
Step-by-step explanation:
perimeter of Base=2(l+w)=2(11+10)=2×21=42 cm
lateral area =perimeter of Base×height=42×5=210 cm²
Hello!
The formula for the area of a triangle is a=1/2bh. Our area is 10. This means that it was half of 20. 20/5 is 4.
The basis is is four square inches.
Hope this helps!