# What should I do if my scientific calculator is showing the dimension error for small matrix multiplication also?

## Dimension error in calculator matrix

If your matrices donu2019t have compatible dimensions, you will get this error.

,When multiplying matrices, the inner values much match.

For example you can multiply a 2x3 by a 3x2.

,Multiplying a 2x2 by a 3x2 would be undefined.

,There are other conditions that cause a dimension error, but this is the common one for matrices.

## How to solve 3x3 matrix on calculator

Read Spectrum Magazines by Arihant Publication to get tips and tricks.

,Some of the shortcuts that can help you in every engineering examu2026,Star to Delta methodUsing Graphs Method - This trick is restricted to Maths.

In questions where you are asked to find the number of solutions to two equations, or to find the range, you can very easily do this by drawing the graph of the equations without actually finding out the solutions.

,For eg:-,Free Body Diagram Method:- Only thing that matters in mechanics , is to draw its Free Body Diagram correctly.

Whatever the question try to solve it with this method.

but, be wisely.

,,Remember standard results:- Gravitational potential inside a sphere , electric field due to a ring, and the point where it is maximum, Moment of inertia of a cone,a hollow sphere, reduced mass concept, magnetic field due to a wire, Two body oscillations in S.

H.

M,Variation in value of u2018gu2019 etc.

(Deriving these during the exam is a very Bad idea,it kills all your time).

,,Hit and Try Method: If a generic question is given, then you can put the values and check.

For eg.

Put theta = 0u00b0, 30u00b0 ,90u00b0 and so on.

,Ray Diagram Method : Draw the ray diagram and try to visualize what exactly is happening , as it will help you to get around 50% question solved.

Also for the electrostatic and electromagnetism draw the rays and try to make the field rays as it will make the problem more easier.

,,Value Substitution Method - Often when the question consists of a term with multiple xs and ys (or as and bs) and you have to reduce it to a value, just put some numbers in place of x and y and check out the options.

One of the options will match.

For example, if the question says that x, y, z are three numbers in GP, put x = 2, y = 4 and z = 8 or something of this sort.

,The area of any kind of questions like a|x|+b|y|=c is given by (2c^2)/|ab|It has personally saved me a lot of time solving problems like these.

Now for the problems which look like a|x-h|+b|y-k|=c, shift the origin to (h,k), then the equation becomes a|X|+b|Y|=cArea is independent of origin thus we can shift the origin.

Same formula now can be applied.

,Units and Dimensions: Always check for the dimensions in the options and the dimension you are asked to find out.

,u201cJEE never fails to add such questions.

You will at least find one question related to it.

u201dFor eg:-, You are asked to find the pressure.

The question is very lengthy and has many quantities.

The best way is out to see if the options have the same dimensions or not.

If their dimension matches to pressure.

And it is the only option then voila.

You saved a lot of time.

Suppose one of the option was : (Plancks constant u00f7 volume) u221a(acceleration due to gravity/length) .

Here its dimensions matches the dimensions of pressure.

Thatu2019s it.

,,Elimination Method :- You need to be rather smart and careful.

This actually is a very useful physics trick, for example try setting mass terms to infinity and zero and check the asymptotic behavior of the equation.

,,Reverse Engineering : if you come across a difficult or time consuming Integration problem and you are stuck on how to proceed, try differentiating the answer and get to the question.

Since doing differentiation is much easier than doing Integration it wont take much time to solve the problem.

,Mechanism of Organic reactions is important- Be clear with mechanism of some very important reactions like- Aldol condensation, Dehydration of Alcohols, Sn1 and Sn2 ,Benzilic Acid Rearrangement, Reimer Tiemann Reaction etc.

,In mechanics you need good knowledge and new concepts to solve problem efficiently.

,In quadratic equations you can easily find out the no of positive and negative real roots of an equation.

By counting no.

of sign changes in coefficients of x in f(x) we get no of positive roots and no of sign change in f(-x) gives no of negative rules.

,,You can solve a mathematics problem easily using physics principles like fermatu2019s principle.

Just practice a lot of problems from any standard books under proper guidance and you will get used to such tricks.

,In calculations, if the options are not close enough, take approximations.

For example, if x=2.

42, take it as 2.

5.

But, be cautions, this skill requires practice and analysis.

These may save some time.

,,Letu2019s see an IIT JEE problem and trying to see the processu2026,Although it was fact based problem u2026 Just knowing angle A is 90degree can save your 2 minutes time.

Thatu2019s trick.

Save time.

Derivative shortcut differentiationFormulau2014,Take an easy example to understand this trick and differentiate it in just one line.

,Take one more exampleu2026,,Solve limit question based on this pattern in just 5 less second.

,Take an example to understand it.

,,Find out the roots so quickly.

,,You have to be sharp minded man to solve problems by using common methods.

,,Solve Trigonometry this kind of problemu2026,In this question,seeing the options itself one could conclude that a,b, or c could take the final result would anyway be a constant i.

e.

the answer doesnu2019t depend on what values a,b, or c would take.

(as the options given are constants and not in terms of either a or b or c ).

,So for this just input that values for a, b, and c that would make the calculation less tedious.

,And now logically,we would input a=1, b=1 , c=(-2).

Hence, the answer is 3 x tan(inverse)(0) = 0 is the answer.

Letu2019s try to solve a different problem using exact method.

,,what kind of force acting in which side.

,,In between, I have seen some of Youtube shortcuts videos which is useful for aspirants.

,,Trick for faster calculation ,reaction and revision,,Mole based questions to solve quickly,,Bond angle based question can be solved so quickly by this method,,How to find bond angle easilyu2026,,VSEPR THEORY,,Integration Shortcut methodu2026,,Find out inverse of a 3x3 Matrix quickly,Shortcuts in Limit based question,,Jee mains and advanced exams arenu2019t Banking, SSC .

.

.

etc like exams in which you can solve every question by using some trick.

Here, you have to memorize lots of data, direct result of derivation based questions to solve lengthy questions which is not so easy.

Itu2019ll cost you too much in exam if you forgot any single number or result so donu2019t depend on it always.

Use these tools but in limitation so that you wonu2019t forget.

,Make a Short notes of all the chapter , with this you can quick remember all the concepts which act as shortcut.

,But be ware, any trick works only if you know how to solve the question.

Just blind faith on these tricks will be detrimental, as you can easily verify in any trial paper.

,Use common sense in some question , this is also a good shortcut.

,Keep connected me ahead to get useful Gyan to becoming Gyani.

,