Merge pull request #1018 from spamegg1/update-alt-link

update MathForCS dead alternate link

README.md

@@ -188,7 +188,7 @@ Courses | Duration | Effort | Notes | Prerequisites | Discussion
 [Calculus 1A: Differentiation](https://openlearninglibrary.mit.edu/courses/course-v1:MITx+18.01.1x+2T2019/about) ([alt](https://ocw.mit.edu/courses/mathematics/18-01sc-single-variable-calculus-fall-2010/index.htm)) | 13 weeks | 6-10 hours/week | The alternate covers this and the following 2 courses | [high school math](FAQ.md#how-can-i-review-the-math-prerequisites) | [chat](https://discord.gg/mPCt45F)
 [Calculus 1B: Integration](https://openlearninglibrary.mit.edu/courses/course-v1:MITx+18.01.2x+3T2019/about) | 13 weeks | 5-10 hours/week | - | Calculus 1A | [chat](https://discord.gg/sddAsZg)
 [Calculus 1C: Coordinate Systems & Infinite Series](https://openlearninglibrary.mit.edu/courses/course-v1:MITx+18.01.3x+1T2020/about) | 6 weeks | 5-10 hours/week | - | Calculus 1B | [chat](https://discord.gg/FNEcNNq)
-[Mathematics for Computer Science](https://openlearninglibrary.mit.edu/courses/course-v1:OCW+6.042J+2T2019/about) ([alt](https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-042j-mathematics-for-computer-science-spring-2015/index.htm)) | 13 weeks | 5 hours/week | An alternate version with solutions to the problem sets is [here](https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-042j-mathematics-for-computer-science-fall-2005/assignments/). | Calculus 1C | [chat](https://discord.gg/EuTzNbF)
+[Mathematics for Computer Science](https://openlearninglibrary.mit.edu/courses/course-v1:OCW+6.042J+2T2019/about) ([alt](https://ocw.mit.edu/courses/6-042j-mathematics-for-computer-science-fall-2010/)) | 13 weeks | 5 hours/week | An alternate version with solutions to the problem sets is [here](https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-042j-mathematics-for-computer-science-fall-2005/assignments/). | Calculus 1C | [chat](https://discord.gg/EuTzNbF)
 
 
 ### CS Tools