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Consider an isosceles triangle ABC, where AB=AC=1, M is the midpoint of BC, and <BAM=<CAM=x. Use trigonometry to find an expression for BM and by finding BC^2, show that cos2x = 1 - 2(sinx)^2.

Consider the right-angled triangle BAM. We have the hypotenuse and an angle, and want to find the opposite side. Therefore, using SOHCAHTOA, sinx = BM/1, hence BM = sinx. Because M is the midpoint of BC, BC ...
BS
Answered by Blessie S. • Maths tutor
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How is immunity developed after a primary infection by bacteria?

Phagocytosis - A phagocyte detects the bacteria has foreign antigens and so envelops it with its cytoplasm, packaging it into a phagosome via endocytosis. Lysosomes then fuse with the phagosome releasing hyd...
DV
Answered by Daniel V. • Biology tutor
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In some parts of Africa, where malaria commonly occurs, there are higher frequencies of the allele that causes sickle-cell anaemia.

Individuals with the recessive sickle-cell anaemia allele have a lower chance of developing severe malaria. Therefore, they are more likely to survive and reproduce than those without the allele. The allele ...
LN
Answered by Laura N. • Biology tutor
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Describe the differences between active transport and facilitated diffusion.

Facilitated diffusion is a passive process that occurs down a concentration gradient. Active transport requires energy (from ATP) to allow movement of substances against a concentration gradient.
LN
Answered by Laura N. • Biology tutor
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Write a persuasive article on why students should or shouldn't have to wear school uniform

Uniform. The bain of our lives as students. What does it achieve? Oppression. Regimentation. Suppressing our freedom to express ourselves. Teachers and schools insist that as students we should strive to be ...
IH
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