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# I need a C in Maths!!

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1. All I need for maths is a C. In the Edexcel non calculator I think I got from 30-36 depending on how harsh the examiner is. I'm just scared that I won't get a C if I miss up the calculator and they said it will be harder. I basically need 40+ to get a C. How can I improve for the calculator exam?
2. Do practice papers, identify weaknesses, use the textbook to do practice questions in the topics you find yourself losing marks on.

Which topics do you struggle with most?
3. (Original post by Wahrheit)
Do practice papers, identify weaknesses, use the textbook to do practice questions in the topics you find yourself losing marks on.

Which topics do you struggle with most?
SOH CAH TOA and recognizing which topic a question is for example I know how to do Pythagoras theorem but I can't recognize it in a question.
4. (Original post by 0lut0)
SOH CAH TOA and recognizing which topic a question is for example I know how to do Pythagoras theorem but I can't recognize it in a question.
Ok so all triangles stuff. For trig, it might help if you get any question involving a triangle to write down everything you KNOW about a triangle, so side lengths and angles, and everything you DON'T know, so the lengths and angles they don't give you. Then go through this process:

How many angles have they given you? If they have given you two and you need to find the third, remember that ALL triangles have angles inside the triangle adding up to 180 degrees. If they have given you one and the other two are the SAME but you don't know them, then just do 180 minus the one you know and divine the answer by two to get the size of the remaining angles. If neither of these things are true or you're not asked to find an angle, move on to the next step:

Is it a right angles triangle? If they have given you a right angled triangle, your life is a lot easier. If not, say you have an isosceles or equalateral triangle, split it into two right angles triangles.

If you are asked to find the length of a side of a right angles triangle, or different type of triangle you've split into right angles triangles, and they've given you two side lengths, you can always use Pythagoras to find the third. Do that.

If you've gone through all these steps and not found the angle or side which they asked for in the question, it's time to use SOH CAH TOA! The trick here is just to remember what it all means: sinX, where X is an angle, is defined as the length of opposite side over the length of the hypotenuse, for example. If you have all the lengths of the sides of the triangle and need to find an angle, then you can use any of sin/cos/tan to get an equation like sinX = O/H where O is the opposite length and H is the hypotenuse. If you have and angle and a length, say you have the length of the hypotenuse and one of the angles next to the hypotenuse , you can use the same equations sinX = O/H but this time O is the thing you don't know instead of X! You could also you cos and it doesn't really matter which a lot of the time.

Once you have this equation, you'll identify which if X or O or H you need to find, then rearrange it, just like with algebra, so it's on one side by itself. If you need to find X, the way you 'get it out' of sinX is by 'doing' sin^-1 (inverse sin) to both sides of the equation (or cos^-1 or tan^-1 depending on whether sin/cos/tan is what's on the left of the X). This 'inverse sin) does the interesting thing of turning sinX into X, because sin^-1 and sin basically cancel each other out. On the other side, O/H becomes sin^-1(O/H). So if you needed to find X, you know have it by itself on one side and you can use your calculator now to find the number that it's equal to.

If you needed to find a length but you know X, use algebra so when you have something like sinX = O/H, you can move everything around to either get H = O/(sinX) or O = H*sinX. To find sinX, just type it into the calculator with X replaced by the angle.

Hope this helps!
I am in year ten and have been achieving A's/ low A*'s in maths.
want to achieve an A* in my final maths GCSE - so am happy to help

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